I watched something like that about 20 years ago, but I can’t recall the title and it could be from 80s or 90s. It could be a low-budget movie or TV episode.
I only remember a scene, when someone (a boy?) was telling a legend his friend about a naked woman who strangled men with her hair (she was female strangler - a witch? a mermaid? ). It took place on some island, and the legend turned out to be true. It is possible that the boy who mocked the legend was actually attacked and strangled by this supernatural woman. I remember a scene where she was seen with her back to the viewer, completely naked and with very long hair.
It is extremely tough to find. It could be something like Animal X (TV Series), so it is hard to find.