Aver is from Old French-Medieval French
averer, from Medieval Latin
adverare, to confirm as authentic, from Latin
ad-,
ad- + Medieval Latin
verare, from Latin
verus, true. Other words deriving from
verus are
very, which sometimes has the sense of "true";
verify, to prove the truth of; and
verdict, a decision or judgment, literally a "true-saying" (
verus +
dictum, saying).