Read the dictionary definition of ascertain. All definitions for this word.
1. be careful or certain to do something; make certain of something
1. He verified that the valves were closed
2. See that the curtains are closed
3. control the quality of the product
2. learn or discover with certainty
3. establish after a calculation, investigation, experiment, survey, or study
1. find the product of two numbers
2. The physicist who found the elusive particle won the Nobel Prize
4. find out, learn, or determine with certainty, usually by making an inquiry or other effort
1. I want to see whether she speaks French
2. See whether it works
3. find out if he speaks Russian
4. Check whether the train leaves on time