Did I do it? Was it enough? Was giving everything over to you, keeping up the game, promising to marry Peeta enough?
In answer, he gives an almost imperceptible shake of his head.
Catching Fire, p.74
"Convince me," Snow said. It seems, under that hot pink sky with Peeta’s life in limbo, I finally did. And in doing so, I gave him the weapon he needed to break me.