I just realized that is the same question Rose asked him on Bad Wolf Bay, and all he could tell her was, "You can't." He knew he'd have the possibility of seeing Donna again, but that he'd never see Rose again.
David interviewed by a wee reporter for The Pirates - Band of Misfits. Absolutely *adorable* the way he gets down on their level and treats them so seriously. And when the kid shakes with his left hand, David doesn't miss a beat. :) I heart David Tennant