verb establish after a calculation, investigation, experiment, survey, or study.
— synonyms: determine, find, find_out
verb be careful or certain to do something.
— synonyms: see, check, insure, see_to_it, ensure, control, assure
verb find out, learn, or determine with certainty, usually by making an inquiry or other effort.
— synonyms: determine, check, find_out, see, watch, learn