Byzantium

The girl writes in a book about her story which will never be told to anyone. Her mother drinks human blood - she's a vampire. Some humans know about it and from there in the trailer there was many cuts featuring action scenes suggesting when people started finding out it created a complication. Also the girl wasn't keen on being a vampire and wasn't a true one as she told her boyfriend suggesting she may not want to be vampire.
The movie is a Hybrid - Thriller because it's jumpy from the vampire attacks and it excites the audience. Also it's a Fantasy because it features vampires and vampires are made up creatures.