A girl named Viola and looking for a roommate, strange thriller movie

The female protagonist is looking for a roommate. She meets a girl named Viola (the name is fairly certain), who acts very provocatively from the start, leading to a romantic connection between the two women. This, in turn, sets off a series of problems for the main character; the film was either a thriller or a drama. That much I’m fairly certain of; it’s possible that both women were brunettes (one definitely was).

Any idea?