1950 film by Frank Tuttle, Borys Lewin

Muichkine, a young Russian prince, returns home to St. Petersburg from a mental institution, determined to spread decency and kindness in the harsh and cruel world. He becomes betrothed to an innocent young girl while trying to save a less-innocent woman from her own travail, but jealousy and his own naivete conjoin to bring about unimaginable tragedy.