"The Youthful Conventioneer" joke

While he was struggling with a jammed cigarette machine in the lobby of his hotel, the youthful conventioneer's hand slipped off the knob and his elbow struck a passing girl on the chest.
"I'm terribly sorry," the man said. "But if your heart is as soft as your breast, you'll forgive me."
"Oh, I do," she answered with a warm smile. "And if the rest of you is as hard as your elbow, my room is 613."