I bought a house with my girlfriend and have now split she never paid a penny and she won't let me sell

I bought a house with my girlfriend we split 9 months ago I want to now sell the house how much is she entitled to

You will have to sue her for partition to find out.

I often wonder what unmarried couples, who buy a house together, are thinking: There is no divorce option in case the relationship goes sour. Therefore partition, a much rarer legal remedy, is the only remaining choice. And, frequently, a mortgage can complicate that. Perhaps a better question to ask is this: What are the bankers thinking when they offer mortgages to unmarried couples?

What are the bankers thinking when they offer mortgages to unmarried couples?

Profits??

Anyway, if you are equally listed as owners she is entitled to half the profits of the sale.