"Can you know for certain that you're not interested when you've never met her?" Naru countered.

Really, he knows that Nagi is focused on his career, but that's sort of exactly the dilemma to Naru. It doesn't seem healthy for career to be the only important thing in a person's life. And he knows Nagi isn't as much of a social butterfly as he is. That's why as his friend it only makes sense for him to use his own charm to help Nagi meet more people.