Monsieur Verdoux

Monsieur Verdoux is a 1947 black comedy film directed by and starring Charles Chaplin, who plays a bigamist wife killer inspired by serial killer Henri Dsir Landru. The supporting cast includes Martha Raye, William Frawley, and Marilyn Nash.

Verdoux develops a poison untraceable by autopsy to use as a better means to kill. He meets The Girl Nash on a rainy night on the street, takes her in, and gives her poisoned wine along with eggs and toast. She thanks him for his kindness, remarks about love, her dead husband who served in the war, and how she still believes in love. Verdoux changes his mind as she is about to sip the wine, and he spares the girl. She leaves unknowing of his cynical intentions.Verdoux makes several attempts to murder Annabella Bonheur, including by strangulation while boating, and by poisoned wine, but she manages to escape unknowingly while putting Verdoux himself in danger or near death. Grosnay eventually relents to the continual flowers from Verdoux and invites him to her residence. Verdoux convinces her to marry him, and Grosnays friends hold a large public wedding to Verdouxs disapproval. Unexpectedly, Bonheur shows up to the wedding. Panicking, Verdoux fakes a cramp to avoid being seen and eventually deserts the wedding. ........

Source: Wikipedia