"Okay. Yeah." Dean rests his forehead on the steering wheel for a moment before sitting up straight and getting the car moving again. "You're an idiot, just so you know. And I'm not sayin' that lightly, you out-idiot all the idiots, and coming from me, that's pretty impressive. And I dunno if I can trust you like I used to, but I am not leaving you, Cas. I'm just not."

Or he's not letting Castiel get away this time is what he means. It just came out a little bit sideways.