"Just replacing the enochian on your ribs." He's not enjoying causing Dean pain, but he does enjoy Dean and his many loud and emphatic responses to things. Dean's so different from everyone else he knows. For lack of a better explanation, Dean is just... alive.

"Now they won't be able to find you as easily again." He'll give Dean every advantage to stay alive and safe here, no matter the personal cost to himself. Dean dragged him through Purgatory; he forgave Castiel and for that, Castiel will never be able to fully repay Dean.