affirm

(verb) establish or strengthen as with new evidence or facts. Synonyms: confirm, corroborate, sustain, substantiate, support. Examples: "His story confirmed my doubts." "The evidence supports the defendant."

(verb) to declare or affirm solemnly and formally as true. Synonyms: verify, assert, avow, aver, swan, swear. Examples: "Before god i swear i am innocent."

(verb) say yes to.