Attest

To bear witness to; to certify; to affirm to be true or genuine; as, to attest the truth of a writing, a copy of record.

To give proof of; to manifest; as, the ruins of Palmyra attest its ancient magnificence.

To call to witness; to invoke.

Witness; testimony; attestation.

authenticate, affirm to be true, genuine, or correct, as in an official capacity; "I attest this signature"

establish or verify the usage of; "This word is not attested until 1993"

provide evidence for; stand as proof of; show by one's behavior, attitude, or external attributes; "His high fever attested to his illness"; "The buildings in Rome manifest a high level of architectural sophistication"; "This decision demonstrates his sense of fairness"