Wouldn't you want to be a better person if you learned that you betrayed all your friends?
I guess it's hard to trust him. I didn't see it coming then, and I keep wondering what happened, what changed, or if maybe nothing changed at all and I just don't know him the way I think I do. When I thought it was Sirius, I spent a year trying to understand it. I thought maybe it was his family getting to him, or he was just always wicked and we didn't know.