Verbs

(v)attest, certify, manifest, demonstrate, evidenceprovide 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”
(v)attestauthenticate, affirm to be true, genuine, or correct, as in an official capacity“I attest this signature”
(v)testify, attest, take the stand, bear witnessgive testimony in a court of law
(v)attestestablish or verify the usage of“This word is not attested until 1993”