verb
attest
uh-TEST/əˈtest/
To confirm or serve as evidence that something is true.
The museum expert attests to the antique object's authenticity after checking its record.

Etymology
The pieces express “bear witness to.” Attesting that something is true or genuine treats confirmation as testimony: a witness or evidence supplies support for accepting the claim.
In context
a look of sorrowful affection seemed to attest her utter guiltlessness
More examples
- The surviving letters attest to her influence on the movement.
- A notary attested the signature on the document.
- The marks on the floor attest to years of heavy use.
Forms
attest · attests · attested · attesting
attestation noun — A formal confirmation or statement of evidence.