see vs ascertain

see is a noun but ascertain is not a noun.

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

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

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

As verbs, see and ascertain are synonyms defined as:

see and ascertain: be careful or certain to do something; make certain of something

Other synonyms of see include assure, check, control, ensure, insure, see to it.

As verbs, see and ascertain are synonyms defined as:

see and ascertain: find out, learn, or determine with certainty, usually by making an inquiry or other effort

Other synonyms of see include check, determine, find out, learn, watch.

see (noun)	ascertain (noun)
the seat within a bishop's diocese where his cathedral is located

see (verb)	ascertain (verb)
deem to be	be careful or certain to do something; make certain of something
perceive (an idea or situation) mentally	learn or discover with certainty
get to know or become aware of, usually accidentally	find out, learn, or determine with certainty, usually by making an inquiry or other effort
be careful or certain to do something; make certain of something	establish after a calculation, investigation, experiment, survey, or study
deliberate or decide
make sense of; assign a meaning to
find out, learn, or determine with certainty, usually by making an inquiry or other effort
match or meet
receive as a specified guest
imagine; conceive of; see in one's mind
come together
conduct someone someplace
perceive by sight or have the power to perceive by sight
perceive or be contemporaneous with
see or watch
see and understand, have a good eye
observe as if with an eye
undergo or live through a difficult experience
observe, check out, and look over carefully or inspect
date regularly; have a steady relationship with
go to see a place, as for entertainment
go to see for professional or business reasons
go to see for a social visit
take charge of or deal with