Definition from Nolo’s Plain-English Law Dictionary
A will that is created in a way that allows a probate court to easily accept it as the true will of the person who has died. In some states, a will is self-proving when two witnesses sign under penalty of perjury that they observed the willmaker sign it and that he told them it was his will. If no one contests the validity of the will, the probate court will accept the will without hearing the testimony of the witnesses or other evidence. In other states, the willmaker and one or more witnesses must sign an affidavit (sworn statement) before a notary public certifying that the will is genuine and that all willmaking formalities were observed.