attest

certify, attest, witness, vouch mean to testify to the truth or genuineness of something. certify usually applies to a written statement, especially one carrying a signature or seal.

• • certified that the candidate had met all requirements

attest applies to oral or written testimony usually from experts or witnesses.

• • attested to the authenticity of the document

witness applies to the subscribing of one's own name to a document as evidence of its genuineness.

• • witnessed the signing of the will

vouch applies to one who testifies as a competent authority or a reliable person.

• • willing to vouch for her integrity