My Lady's Latchkey (1921)

Young Annesley Grayle, weary of a gloomy, uneventful existence with her aunt, accepts the proposal of a young American that she pose as his wife. Later, they are actually married. When, at a ball, she hears her husband accused of stealing a valuable diamond and realizes that he is indeed a thief, she hides the jewel to save him. She plans to report him to the police, but, seeing that he intends to reform, she remains with him and saves him from being shot by a jealous countess.