I'll go with the generic one, that has been maybe overused by now not only in regards to asoiaf. But honestly I really like it and it's true.
" “Robb says the man died bravely, but Jon says he was afraid.” “What do you think?” his father asked. Bran thought about it. “Can a man still be brave if he’s afraid?” “That is the only time a man can be brave,” his father told him."
I also really like the conversations between Cat and Jaime and Sansa and Sandor, which are in their essence the same with Sansa and Cat holding the same position opposing Jaime's and Sandor's (which is also the same or at least very similar). The good thing about them is, that there is truth to both positions, how it is often in life. And most importantly it's each characters' personal truth and closely connected to their identity, they are completely honest here, which we don't don't get that often between characters. And GRRM doesn't make a morality tale out of it-hitting you over the head with the "right" opinion.
Cat and Jaime:
" “Why should I tell you anything?” “To save your life.” “You think I fear death?” That seemed to amuse him. “You should. Your crimes will have earned you a place of torment in the deepest of the seven hells, if the gods are just.” “What gods are those, Lady Catelyn? The trees your husband prayed to? How well did they serve him when my sister took his head off?” Jaime gave a chuckle. “If there are gods, why is the world so full of pain and injustice?” “Because of men like you.” “There are no men like me. There’s only me.” (...)
“How did my son Bran come to fall?” “I flung him from a window.” The easy way he said it took her voice away for an instant. If I had a knife, I would kill him now, she thought, until she remembered the girls. Her throat constricted as she said, “You were a knight, sworn to defend the weak and innocent.” “He was weak enough, but perhaps not so innocent. He was spying on us.” “Bran would not spy.” “Then blame those precious gods of yours, who brought the boy to our window and gave him a glimpse of something he was never meant to see.” “Blame the gods?” she said, incredulous. “Yours was the hand that threw him. You meant for him to die.” His chains chinked softly. “I seldom fling children from towers to improve their health. Yes, I meant for him to die.” “And when he did not, you knew your danger was worse than ever, so you gave your catspaw a bag of silver to make certain Bran would never wake.” “Did I now?” Jaime lifted his cup and took a long swallow. “I won’t deny we talked of it, but you were with the boy day and night, your maester and Lord Eddard attended him frequently, and there were guards, even those damned direwolves … it would have required cutting my way through half of Winterfell. And why bother, when the boy seemed like to die of his own accord?” “If you lie to me, this session is at an end.” Catelyn held out her hands, to show him her fingers and palms. “The man who came to slit Bran’s throat gave me these scars. You swear you had no part in sending him?” “On my honor as a Lannister.”
“Your honor as a Lannister is worth less than this.” She kicked over the waste pail. Foul-smelling brown ooze crept across the floor of the cell, soaking into the straw. Jaime Lannister backed away from the spill as far as his chains would allow. “I may indeed have shit for honor, I won’t deny it, but I have never yet hired anyone to do my killing. Believe what you will, Lady Stark, but if I had wanted your Bran dead I would have slain him myself.” Gods be merciful, he’s telling the truth. (...)
“I’ve admitted to shoving your precious urchin out a window, what would it gain me to lie about this knife?” He tossed down another cup of wine. “Believe what you will, I’m past caring what people say of me. (...)
“How can you still count yourself a knight, when you have forsaken every vow you ever swore?” Jaime reached for the flagon to refill his cup. “So many vows … they make you swear and swear. Defend the king. Obey the king. Keep his secrets. Do his bidding. Your life for his. But obey your father. Love your sister. Protect the innocent. Defend the weak. Respect the gods. Obey the laws. It’s too much. No matter what you do, you’re forsaking one vow or the other.” He took a healthy swallow of wine and closed his eyes for an instant, leaning his head back against the patch of niter on the wall. “I was the youngest man ever to wear the white cloak.” “And the youngest to betray all it stood for, Kingslayer.”
“Kingslayer,” he pronounced carefully. “And such a king he was!” He lifted his cup. “To Aerys Targaryen, the Second of His Name, Lord of the Seven Kingdoms and Protector of the Realm. And to the sword that opened his throat. A golden sword, don’t you know. Until his blood ran red down the blade. Those are the Lannister colors, red and gold.” As he laughed, she realized the wine had done its work; Jaime had drained most of the flagon, and he was drunk. “Only a man like you would be proud of such an act.” “I told you, there are no men like me. Answer me this, Lady Stark—did your Ned ever tell you the manner of his father’s death? Or his brother’s?” “They strangled Brandon while his father watched, and then killed Lord Rickard as well.” An ugly tale, and sixteen years old. Why was he asking about it now? “Killed, yes, but how?” “The cord or the axe, I suppose.” Jaime took a swallow, wiped his mouth. “No doubt Ned wished to spare you. His sweet young bride, if not quite a maiden. Well, you wanted truth. Ask me. We made a bargain, I can deny you nothing. Ask.” “Dead is dead.” I do not want to know this. “Brandon was different from his brother, wasn’t he? He had blood in his veins instead of cold water. More like me.” “Brandon was nothing like you.” “If you say so. You and he were to wed.” “He was on his way to Riverrun when …” strange, how telling it still made her throat grow tight, after all these years “… when he heard about Lyanna, and went to King’s Landing instead. It was a rash thing to do.” She remembered how her own father had raged when the news had been brought to Riverrun. The gallant fool, was what he called Brandon. Jaime poured the last half-cup of wine. “He rode into the Red Keep with a few companions, shouting for Prince Rhaegar to come out and die. But Rhaegar wasn’t there. Aerys sent his guards to arrest them all for plotting his son’s murder. The others were lords’ sons too, it seems to me.” (...)
“Aerys …” Catelyn could taste bile at the back of her throat. The story was so hideous she suspected it had to be true. “Aerys was mad, the whole realm knew it, but if you would have me believe you slew him to avenge Brandon Stark …” “I made no such claim. The Starks were nothing to me. I will say, I think it passing odd that I am loved by one for a kindness I never did, and reviled by so many for my finest act. At Robert’s coronation, I was made to kneel at the royal feet beside Grand Maester Pycelle and Varys the eunuch, so that he might forgive us our crimes before he took us into his service. As for your Ned, he should have kissed the hand that slew Aerys, but he preferred to scorn the arse he found sitting on Robert’s throne. I think Ned Stark loved Robert better than he ever loved his brother or his father … or even you, my lady. He was never unfaithful to Robert, was he?” Jaime gave a drunken laugh. “Come, Lady Stark, don’t you find this all terribly amusing?” “I find nothing about you amusing, Kingslayer.” “That name again. I don’t think I’ll fuck you after all, Littlefinger had you first, didn’t he? I never eat off another man’s trencher. Besides, you’re not half so lovely as my sister.” His smile cut. “I’ve never lain with any woman but Cersei. In my own way, I have been truer than your Ned ever was. Poor old dead Ned. So who has shit for honor now, I ask you? What was the name of that bastard he fathered?” Catelyn took a step backwards. “Brienne.” “No, that wasn’t it.” Jaime Lannister upended the flagon. A trickle ran down onto his face, bright as blood. “Snow, that was the one. Such a white name … like the pretty cloaks they give us in the Kingsguard when we swear our pretty oaths.”
Sandor and Sansa:
"She hated the way he talked, always so harsh and angry. “Does it give you joy to scare people?” “No, it gives me joy to kill people.” His mouth twitched. “Wrinkle up your face all you like, but spare me this false piety. You were a high lord’s get. Don’t tell me Lord Eddard Stark of Winterfell never killed a man.” “That was his duty. He never liked it.” “Is that what he told you?” Clegane laughed again. “Your father lied. Killing is the sweetest thing there is.” He drew his longsword. “Here’s your truth. Your precious father found that out on Baelor’s steps. Lord of Winterfell, Hand of the King, Warden of the North, the mighty Eddard Stark, of a line eight thousand years old … but Ilyn Payne’s blade went through his neck all the same, didn’t it? Do you remember the dance he did when his head came off his shoulders?” Sansa hugged herself, suddenly cold. “Why are you always so hateful? I was thanking you …” “Just as if I was one of those true knights you love so well, yes. What do you think a knight is for, girl? You think it’s all taking favors from ladies and looking fine in gold plate? Knights are for killing.” He laid the edge of his longsword against her neck, just under her ear. Sansa could feel the sharpness of the steel. “I killed my first man at twelve. I’ve lost count of how many I’ve killed since then. High lords with old names, fat rich men dressed in velvet, knights puffed up like bladders with their honors, yes, and women and children too—they’re all meat, and I’m the butcher. Let them have their lands and their gods and their gold. Let them have their sers.” Sandor Clegane spat at her feet to show what he thought of that. “So long as I have this,” he said, lifting the sword from her throat, “there’s no man on earth I need fear.” Except your brother, Sansa thought, but she had better sense than to say it aloud. He is a dog, just as he says. A half-wild, mean-tempered dog that bites any hand that tries to pet him, and yet will savage any man who tries to hurt his masters. “Not even the men across the river?” Clegane’s eyes turned toward the distant fires. “All this burning.” He sheathed his sword. “Only cowards fight with fire.” “Lord Stannis is no coward.” “He’s not the man his brother was either. Robert never let a little thing like a river stop him.” “What will you do when he crosses?” “Fight. Kill. Die, maybe.” “Aren’t you afraid? The gods might send you down to some terrible hell for all the evil you’ve done.” “What evil?” He laughed. “What gods?” “The gods who made us all.” “All?” he mocked. “Tell me, little bird, what kind of god makes a monster like the Imp, or a halfwit like Lady Tanda’s daughter? If there are gods, they made sheep so wolves could eat mutton, and they made the weak for the strong to play with.” “True knights protect the weak.” He snorted. “There are no true knights, no more than there are gods. If you can’t protect yourself, die and get out of the way of those who can. Sharp steel and strong arms rule this world, don’t ever believe any different.” Sansa backed away from him. “You’re awful.” “I’m honest. It’s the world that’s awful."