aver (v.)

late 14c., "assert the truth of," from Old French averer "verify, confirm, prove" (12c.), from Vulgar Latin *adverare "make true, prove to be true," from Latin ad "to" (see ad-) + verus "true" (from PIE root *were-o- "true, trustworthy"). From 1580s as "affirm with confidence." Related: Averred; averring.