Certify

To give cetain information to; to assure; to make certain.

To give certain information of; to make certain, as a fact; to verify.

To testify to in writing; to make a declaration concerning, in writing, under hand, or hand and seal.

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"

guarantee as meeting a certain standard; "certified grade AAA meat"