bear witness vs certify

bear witness and certify both are verbs.

Word	Noun	Adjective	Verb	Adverb
bear witness	No	No	Yes	No
certify	No	No	Yes	No

As verbs, certify is a hyponym of bear witness; that is, certify is a word with a more specific, narrower meaning than bear witness:

bear witness: provide evidence for
certify: provide evidence for; stand as proof of; show by one's behavior, attitude, or external attributes

Other hyponyms of bear witness include attest, demonstrate, evidence, manifest, presume, abduce, adduce, cite.

bear witness (verb)	certify (verb)
give testimony in a court of law	provide evidence for; stand as proof of; show by one's behavior, attitude, or external attributes
provide evidence for	declare legally insane
	guarantee payment on; of checks
	guarantee as meeting a certain standard
	authorize officially