Homicidal (1961)

"A WORD OF WARNING! Please don't reveal the ending of this picture or your friends will kill you - IF THEY DON'T, I WILL!"

A woman named Emily checks into a hotel and offers the bellboy $2000 to temporarily marry her. We soon find out Emily is the caretaker of a wheelchair-bound mute named Helga, who was the childhood guardian of a pair of siblings: Miriam Webster and her half-brother, Warren, who is about to inherit the estate of their late father. Who is the mysterious Emily and what are her intentions?