Draco's unexpected request startled Hermione enough that she wasn't sure how to answer. After almost constant questions from her that he refused to answer, it was tempting to tell him "no'. But, perhaps it could also be a way for her to finally get at least some answers. She hadn't gotten as far as she had without using her brain or begging for information. In a similar manner to his, Hermione felt the corner of her mouth curl up into a smirk.