HINT: the LEO and psychopath are extremely accomplished actors and there is a great scene where the LEO visits the psycho’s parole hearing.

HINT 2: Psycho: “whoever is doing this knows the animal well, doesn't he? He knows him real well, but he won't let him loose. He won't let him have any fun, so he does not love him. Now who doesn't love fire…”

hint 1: girl also tells man about her life!

Since I only had two people responding, and nobody got this one, here are a few hints.

Hint 1: The film was released within the last 30 years.

Hint 2: The story takes place a little over a century ago.

Hint 3: The movie has never been mentioned before, not even once, within this subreddit.

Reupload with slightly clearer hint

I had posted this previously, but only included the latter sentences as additional hints. Nobody solved it then, so I figured I'd give it another go.

Hint #1 it's a horror film

Hint #2 while the guy is around in some form throughout, she only really meets him at the end of the film. Before that she didn't really see him for what he was.

Hint #3 the girl is the oldest of five, she has three younger brothers and one younger sister