“Is that a certainty?”

YOU SURE?

Think of a casual way to double-check someone’s confidence, often said with a slight rise in tone at the end.

The clue plays on the phrase "you sure?"—a casual way to ask if something is certain. The quotation marks signal that the answer is a spoken expression rather than a literal definition. It’s a direct lift of the question itself, turning the clue into a self-referential pun where the answer mirrors the doubt implied in the question.