For sure Definition 1 of 3Pro Tip 1/3Emphasis Use 'for sure' to stress certainty in predictions or statements. She will win the competition, for sure. Pro Tip 2/3Casual Tone 'For sure' gives a casual and friendly tone to conversations. They're the best tacos in town, for sure. Pro Tip 3/3Avoid Overuse Using 'for sure' too often can make it lose its impact. I say 'for sure' a lot, but I mean it this time.