[That's possibly the sweetest thing someone has said to him in a long time, and so this time, when Claude is caught off guard for a moment, it's because he's genuinely flattered, not perplexed.]

Thank you, Byleth. [He says it softly, once he finds his voice again.] To be honest, I spent a lot of my life faced with people who wanted to fit me into boxes, and then used that as an excuse to treat me like... [he trails off, decides on the polite word he uses for it:] --an outsider. It hurt, but it's how it always was for someone like me.

So for you to have a preconception of me, but to be able to reexamine it based on your experiences... It's a little thing, but it makes me very happy.

[Even finding people as confusing as he does, that fact alone makes Byleth way better than all those other people combined.]