certify

(verb) provide evidence for; stand as proof of; show by one's behavior, attitude, or external attributes. Synonyms: attest, manifest, demonstrate, evidence. Examples: "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."

(verb) guarantee payment on; of checks.

(verb) authorize officially. Synonyms: license, licence. Example: "I am licensed to practice law in this state."

(verb) guarantee as meeting a certain standard. Synonyms: endorse, indorse. Example: "Certified grade aaa meat."

(verb) declare legally insane.