hear vs ascertain

hear and ascertain both are verbs.

Word	Noun	Adjective	Verb	Adverb
hear	No	No	Yes	No
ascertain	No	No	Yes	No

As verbs, ascertain is a hyponym of hear; that is, ascertain is a word with a more specific, narrower meaning than hear:

Other hyponyms of hear include get the goods, wise up, catch, trip up.

hear (verb)	ascertain (verb)
get to know or become aware of, usually accidentally	be careful or certain to do something; make certain of something
perceive (sound) via the auditory sense	learn or discover with certainty
receive a communication from someone	find out, learn, or determine with certainty, usually by making an inquiry or other effort
listen and pay attention	establish after a calculation, investigation, experiment, survey, or study
examine or hear (evidence or a case) by judicial process