Bava Batra 51 - When One Sells Land to his Wife
If a man sold land to his wife, and she bought it with money that he knew nothing about till now, he can claim that he only wanted to discover the source of her hidden funds, but not to really sell the field, and thus reverse the sale. However, if she buys it with money he had known from before, the sale is final.
The best way to sell the field to one's wife is to write both terms in the contract, "the field is sold to you" and "the field is given to you." The sale term will help her if the field is repossessed by the husband's lenders - by giving her the right to be reimbursed by the husband. The term "given" will help against a neighbor's right to buy an adjoining field .