He actually talked about whether or not he wanted to get to know the person he thought she is, or the person she truly is, in that very episode. I'd actually like to call that evidence, if you will, considering he basically laid out not only his confession, but his reservations. He has no idea if the person he's been pining over for 10 years is the same person standing in front of him.
He's shown multiple times throughout the entire series that he basically thinks she's some angel, and that he can't so much as even talk to her.
I mean, I'm just stating the facts here. I think they're cute, but I don't see this ship lasting much longer.