It's not that any of this makes him happy. He's forgotten how to be happy, if he ever knew. When there's a smile on Rin's face, when he's at her side and she's content, when he tends to her needs in this peaceful town, sometimes he thinks he might remember, but it's fleeting. It's not really any of that. It's just that he can't disentangle the dreams he once followed from Rin anymore. If fighting to save people is what makes a hero, and she's the most precious person in this world, then shouldn't he stay at her side?

He thinks that probably doesn't make sense if he examines it too closely. But he just won't examine it too closely anymore.

Especially if she's going to say troubling things like that.

"I see." His cheeks are flushed. "You'll continue to have absurd misapprehensions. Rin, I'm not asking you to die." He reaches for her hand. "I'm asking you to live and let me live at your side. And I'll have you know that I refuse to let you be bound by such nonsense as 'magi don't live very long lives.' I'm going to look forward to a time when I stop dying my hair so we can both be old and grey together."

He's saying impossible things, but he doesn't care. He'll keep saying impossible things for her.