ascertain
/ˌa-sər-ˈtān/
verb
to find out or learn with certainty
to make certain, exact, or precise
ascertain the truth
discover ascertain determine unearth learn mean to find out what one did not previously know. discover may apply to something requiring exploration or investigation or to a chance encounter. ascertain implies effort to find the facts or the truth proceeding from awareness of ignorance or uncertainty.