ascertain from
To find out something from examining or observing something or some situation. A noun or pronoun can be used between "ascertain" and "from." I ascertained a lot about my daughter's new boyfriend from our first dinner together. What were you able to ascertain from the article?
ascertain something from someone or something
to find out or learn with certainty information from someone or something. I need to ascertain some facts from you. A few facts have been ascertained from the interview.