Welcome to Wiki. I assume you are not married. The ruled are very different.
Is the house in your sole name?
If you are not married and she is not on deeds then her only claim would be under property law. She could make a claim based on having a beneficial interest. If you search the site using the search bar at the top of the page, you will find information to help you.
It can be a messy and expensive procedure. To avoid this sort of thing, we normally suggest you agree to pay some ''go away'' money. The amount will depend on you and your circumstances but it should be at least enough for a deposit and a few months rent if possible.