Sam is also relieved the angel isn't following their every move; something about the way Castiel looks at him makes him feel uncomfortable or judged. He'd be relieved to know Ruby doesn't have that complication either if he knew what she thought. Yes, too many arguments might break them apart, and Sam doesn't want that when he just got Dean back. Unfortunately, Sam can't help Dean understand his mental abilities or connection to Ruby. That may just take time following the conversation.

Instinctively, Sam points to the road as Dean should pay attention to the traffic (namely the big rig closest to them). But he doesn't blame Dean for that expression and puts careful thought into an explanation. "You weren't there." Only so many ways he can pull the punches with that nugget of truth, but his voice is steady and calm. "She could have killed me if that's what she wanted to do; trust me, she had multiple opportunities. Instead she's gone out of her way to help me figure out my next steps. So as far as I'm concerned, she's earned my trust through her actions. She is different. We can't classify people as all good, law abiding citizens; I won't classify her as bad as the rest of them when all she's done is help. I think you should give her a chance to prove it. I can't help you understand if you don't."