To Affi'rm. v.a. To ratify or approve a former law, or judgment: opposed to reverse or repeal.
The house of peers hath a power of judicature in some cases, properly to examine and then to affirm; or, if there be cause, to reverse the judgments which have been given in the court of king's bench. Bacon's Advice to Sir G. Villiers.
In this sense we say, to affirm the truth.