"He will," Draco said simply.  Pansy probably assumed he meant that he'd somehow coerce the man into doing what he wanted.  That was the Malfoy way, after all, and she probably put a lot more faith into his blackmailing and bullying skills than Potter's innate goodness.  He was happy to let her think that.  Whatever made her sag in relief that, even if it took a week, some form of balm was coming was fine with him.