Ascertain

"Ascertain" means:


 * 1) Learn with certainty or assurance.
 * 2) Determine.
 * 3) Archaic. to make certain, clear, exact, precise or definitely known.
 * 4) To find out or learn with certainty.


 * Sources: https://www.merriam-webster.com/dictionary/ascertain and http://www.dictionary.com/browse/ascertain.