1. finding out for certain; discovering the truth about something through investigation or inquiry
Usage: present participle of ‘ascertain’

Examples

• The detective is ascertaining the facts of the case.
• We are ascertaining whether the report is accurate.
• The scientist spent months ascertaining the cause of the phenomenon.
• Before making a decision, she is ascertaining all the relevant information.
• The committee is ascertaining the best course of action.
• He is ascertaining the identity of the mysterious caller.