Legal Question in Real Estate Law in California

She can't sell it without your approval. She may or may not be able to revoke the trust without your approval. If you are both trustees of the trust and both beneficiaries, you have a pretty convoluted legal problem here, involving both trust law and partition of real property. You could spend a lot of money fighting each other on something like this. Have you considered mediation?

Unless you have an agreement otherwise, to force you to sell she'd have to file a partition action in court. It's expensive, and the fees and costs are taken from the proceeds, so it may be helpful to work out a deal outside of court. As the other attorney suggested, mediation with a professional mediator who has a background in real estate law.