certify

sense 1: 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"
attest certify manifest demonstrate evidence

sense 2: guarantee payment on; of checks
certify

sense 3: authorize officially
license licence certify

sense 4: guarantee as meeting a certain standard; "certified grade AAA meat"
certify endorse

sense 5: declare legally insane
certify