You searched for: “avouch
avouch, avouches, avouched, avouching (verb forms)
1. To declare the provable truth or validity of; to affirm: "The father avouched that his son could not have committed the crime."
2. To corroborate or to confirm; to vouch for: "Was the police officer able to avouch his accusations?"
3. To accept responsibility for (an action, for example); to acknowledge.
4. To avow; to confess.
5. Etymology: from Middle French avochier, "call upon as authority"; from Old French and Latin advocare, "to call to" as a witness.