Unfortunately, without a written agreement, you seem to have no recourse. In Texas (and most states with which I am familiar), a contract or agreement regarding the purchase of real estate must be in writing to be enforceable: an oral or unwritten ("oral, not "verbal," is the correct term, by the way) agreement for the sale or transfer of real estate will not be enforced by the courts. Since your oral agreement is not enforceable, you in essence simply gifted or gave the house to her.