attest

Short definition from Wiktionary

Verb

1. 1
   To affirm to be correct, true, or genuine.
2. 2
   To certify by signature or oath.
3. 3
   To certify in an official capacity.
4. 4
   To supply or be evidence of.
5. 5
   To put under oath.
6. 6
   To call to witness; to invoke.