Supernatural, Season 8

Sam:
You want to know what I confessed in there? What my greatest sin was? It was how many times I let you down. I can't do that again.

Dean:
Sam...

Sam:
[Crying] What happens when you've decided I can't be trusted again? I mean, who are you gonna turn to next time instead of me? Another angel, another... another vampire? Do you have any idea what it feels like to watch your brother just...

Dean:
Hold on, hold on! You seriously think that? Because none of it... none of it... is true. Listen, man, I know we've had our disagreements, okay? Hell, I know I've said some junk that set you back on your heels. But, Sammy...come on. I killed Benny to save you. I'm willing to let this bastard and all the sons of bitches that killed mom walk because of you. Don't you dare think that there is anything, past or present, that I would put in front of you! It has never been like that, ever! I need you to see that. I'm begging you.