He can tell that his interests may not line up with this girl's--and while that was fine, the teacher in him flares up, and he has to suppress a small laugh.

"If nothing else, it would be a rare piece of memorabilia for your time spent in this place."

Because while others may pick up things like jewelry or necklaces, or those weird-as-hell glowing tattoos to 'bring home', how many could boast that they aquired a booklet deciphering and notating the language of the mysterious, once-lost land?

Vergil himself felt like he'd aquired something quite impressive, so...

"At least, that is my opinion on it. I have been told my tastes are ... eccentric."