attest

verb

1. (transitive)To affirm to be correct, true, or genuine.

   “When will the appraiser attest the date of the painting?”

   “Dishonour not your Mothers: now attest that those whom you call'd Fathers, did beget you.”

   “[W]e have already ſeen many particular facts vvhich are recorded in holy vvrit, atteſted by particular Pagan Authors: […]”

   “As the Wildlings can attest, there’s already new life even north of the wall, poking up through the ice. Winter only lasts so long.”

2. (transitive)To certify by signature or oath.

   “You must attest your will in order for it to be valid.”

3. (transitive)To certify in an official capacity.
4. (ambitransitive)To supply or be evidence of.

   “Her fine work attested her ability.”

   “O pardon : since a crooked Figure may / Attest in little place a Million, / And let us, Cyphers to this great Accompt, / On your imaginarie Forces worke.”

   “The supplementary bibliography (in Vol. VI) attests to the comprehensiveness of the effort.”

5. (transitive)To put under oath.
6. (obsolete, transitive)To call to witness; to invoke.

   “The sacred streams which Heaven's imperial state / Attests in oaths, and fears to violate.”