Legal Question in Credit and Debt Law in Washington

Yes. Verbal agreements are valid and enforceable, the challenge is the evidence required to prove them. Plaintiff's testimony may be sufficient, but if the other person testifies to the contrary Plaintiff may have a problem as the burden is on the Plaintiff. The more credible testimony will be given more weight and often, although the agreement was not written, there is a record created in the course of dealing which may help in proving the agreement.