"Er—I'm not that interesting, really. And things Malfoy tells ... he'll make them sound more ... interesting than they really are." Yes, that's the way to approach it. Harry has never seen himself as interesting. Willing to fight to do what's necessary? Sure, he's always seen himself as that person, much to the chagrin of many (even those on the side of good). But interesting is far from the case.

"But yes, let's go." He wants to ask how she knows Malfoy, and he knows he'll ask in time, but somehow, he feels like it's a tense conversation. Harry doesn't know if he'll be able to keep back any of his own remarks about Malfoy's true (or perceived) nature.