I know enough, [ she says wryly, quietly. not everything, no — but so much that many think it to be the same thing. ]

Dean. You convinced Castiel once, didn't you? You showed him why humanity is worth it. You'll do it again. It's who you are.

[ it's in his nature. and in any case — ]

In the end, Castiel believed in you. Sam has always believed in you. Maybe... it's time you start believing in yourself.