Deadly Illusions (2021)

Mary then travels to Grace's hometown and visits her aunt, who reveals Grace had been abused by her parents as a child. Mary calls Tom to warn him about Grace but he does not answer. Back home, Tom is in the shower when Grace walks in dressed in lingerie and brandishing a large knife. She continuously switches from her usual sweet, soft-toned self to a violent seducer with a deep voice. As she attacks Tom, Mary arrives home. Grace claims to not know what happened to me, repeatedly saying, "I couldn't stop her." It is then revealed that Grace suffers from dissociative identity disorder and that her other identity "Margaret" is who attacked Tom. Mary eventually overpowers Grace, knocking her unconscious.
One year later, Mary and her family are still together. Mary takes the finished manuscript of her new book to Elaine's grave and leaves it there, as it was Elaine who encouraged her to start writing. She then goes to visit Grace in a mental hospital. The film ends with "Mary" leaving the hospital, her face obscured by a headscarf and sunglasses as in the police video.