[He could tell her what she did -- that she was the one who really defeated the Daleks, not him. All he did was come in later and mop up after she took over where he'd failed miserably. Somehow, though, it doesn't strike him that she'd take being told she brought an entire species to heel while under the influence of the Doctor's mind as quite the encouragement it ought to be, if only for the under the influence of the Doctor's mind bit.

Instead, he's just quiet for a moment before he speaks again.] You're a lot more important than you know, Donna Noble, and I wouldn't be surprised if that were as true here as it was back home.