Very unfortunate, but it happens every day. If there is no mortgage, you'll have to share the equity with her.
Is there a mortgage? If so, I assume she's also not on the note so you're the only one who's credit is screwed if you quit paying the mortgage. Perhaps you could arrange a "friendly foreclosure" with the mortgage company, they would own the house a short time, evict her, then sell it back to you. Your credit will take a hit but you could be back in control of 100% of the property. See a lawyer. Good luck.
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You will probably have to file a partition action. You will need to retain a real estate litigation attorney in your area. As previously noted, she is now a owner of the property, so you cannot simply kick her out of the house.
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