Contracts to devise real property are frequently entered into and are generally held to be a valid mode of transferring realty. Very properly the courts view such contracts with suspicion, especially when orally made. In order to prove the contract to devise real property some states require that it be in writing, otherwise it will be deemed void. But the majority of courts are not so strict and an oral contract if adequately proven is satisfactory. However, in proving oral contracts some states require that the contract be proven "independent of the performance" while other courts including Washington are more liberal and admit evidence of performance, or change of position by the promisee as an element of proving the contract itself. The intention of the promisor to contract may be shown either by acceptance of services of the promisee by the deceased promisor, or by any conduct indicating that he presently binds himself to devise or transfer title to the real property in question to the promisee, or simply by conversations of the deceased promisor with disinterested witnesses (an extremely liberal view). The major problem arises when the contract rests in parole, as most often is the case, and the requirements of the Statute of Frauds are encountered.
Willard J. Wright,
Contracts to Devise Real Property,
14 Wash. L. Rev. & St. B.J.
Available at: https://digitalcommons.law.uw.edu/wlr/vol14/iss1/3