Attester

to bear witness to; certify; declare to be correct, true, or genuine; declare the truth of, in words or writing, especially affirm in an official capacity:
to attest the truth of a statement.
to give proof or evidence of; manifest:
his works attest his industry.
to put on oath.
to testify or bear witness (often followed by to):
to attest to the reliability of an employee.
archaic. witness; testimony; .
verb
(transitive) to affirm the correctness or truth of
when intr, usually foll by to. to witness (an act, event, etc) or bear witness to (an act, event, etc) as by signature or oath
(transitive) to make evident; demonstrate: his life of luxury attests his wealth
(transitive) to provide evidence for: the marks in the ground attested the presence of a fossil
v.

1590s, from middle french attester (old french atester, 13c.) “affirm, attest,” from latin attestari “confirm,” literally “bear witness to,” from ad- “to” (see ad-) + testari “bear witness,” from testis “witness” (see testament). related: attested; attesting.