The whisper and kiss on Bad Wolf Bay.
Maybe the viewers didn’t get to hear what the metacrisis Doctor whispered in Rose’s ear, but we all know, unequivocally, he finally got to tell Rose he loved her, after all that time of bottling it up. TenToo, though most certainly the same man, is nevertheless a different kind of creature. Obviously, he is far more human, but not only physically, but mentally. With that touch of human instinct, TenToo was able to release all the emotions the Doctor felt for Rose, while the original Doctor never could. Finally, Rose and the Doctor get their happy ending.