Google Translate is actually almost literate for this:
It's White Day, so I'll give you some white chocolate, Lily.
...Doggone cute guy I wonder...
Well, okay, the second line could use some work. Hence the "almost."
Still, does gaoo have a soft spot for Lily? Or is this one of those "hidden torture" deals (such as, Lily being highly allergic to chocolate)? With gaoo, you never know.