The Cardboard Lover
A ditzy American girl visiting Monte Carlo is hired by a tennis champ to be his "cardboard lover"--to pretend to be in love with him so he can teach his two-timing fiancé a lesson and win her back. What he doesn't realize is that the girl isn't pretending --she actually is in love with him, and she sets out to win him for herself.
Directors: Robert Z. Leonard
Writers: Carey Wilson, Jacques Deval, Lucille Newmark
IMDB: tt0018749