[he didn't actually know that was a thing for half-demons but now that he does...

it's just too sad?

but especially when Rin says all of that and still...]

I'm just... not certain I'm someone who should have something like that. It's really... too selfish. [there's a bit of a pause before he laughs. in a helpless manner.] I'm just this selfish sort of person who doesn't know what they are, runs from duty, and causes chaos wherever I go.

[if it sounds like he's echoing something he's heard, it's because he is. and he can't really refute it, either.]