Which word means to find out something with certainty?

The word "ascertain" is used to describe the act of discovering something with certainty, confirming facts or information, or establishing the truth of a situation through investigation or inquiry. In practical terms, when you ascertain something, you are not just guessing or making assumptions; you are engaged in a process that involves verifying and gathering evidence to support your conclusion.

For example, if you were to ascertain the cause of a problem, you would systematically check various factors and pieces of information until you arrive at a clear and confirmed answer. This concept is fundamental in many fields, including research, law, science, and everyday problem-solving, where clarity and certainty are crucial.

In contrast, the other options do not convey this meaning. "Articulate" refers to the ability to express ideas clearly, "aversion" indicates a strong dislike or avoidance of something, and "audacious" describes someone who is bold or daring, often in a way that is recklessly brave. None of these words imply the process of discovering or confirming information with certainty.