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
Example Sentences
I can attest that what he has said is true. The certificate attests the authenticity of the painting.
Recent Examples on the WebHer skepticism is fair, as Children of the Underground might attest. Sophie Gilbert, The Atlantic, 1 Sep. 2022 Those other extracurricular activities might be even more impressive than being a two-year starter at right guard, and Penny is plenty good at that, as his teammates can attest. Matt Le Cren, Chicago Tribune, 1 Sep. 2022 As those of us who lived through the decade can attest, this is actually period-appropriate. Chris Willman, Variety, 31 Aug. 2022 As generations of twentieth-century Italian mothers and their children can attest, giving a woman no choice but to anonymously surrender her baby is a route to ruined lives. Maria Laurino, The New Republic, 25 Aug. 2022 But finding the right candidate takes time, as Oregon State can attest.oregonlive, 11 Aug. 2022 As with Murray, the question of Williamson’s talent was as clear as day, as anyone who has seen him at full strength and marveled at the remarkable agility of the big man can attest. Don Yaeger, Forbes, 9 Aug. 2022 As anyone who has recently applied for a passport can attest, U.S. passport agencies are still catching up from the pandemic lockdown. Amanda Foreman, WSJ, 12 Aug. 2022 As anyone who’s out and about can attest, though, many Californians are not heeding that call. Luke Money, Los Angeles Times, 21 July 2022 See More
Word History
Etymology
Middle French attester, from Latin attestari, from ad- + testis witness — more at testament