From Longman Dictionary of Contemporary Englishfor surefor surea) informal certainly or definitely No one knows for sure what really happened. b) spoken used to emphasize that something is true We’ll always need teachers, that’s for sure. c) American English informal spoken used to agree with someone → sure
Examples from the Corpus
that’s for sure• He wasn't using drugs, that's for sure.• Because she was beautiful and couldn't do enough for me, that's for sure.• Certainly not in the Aero-Space industry, that's for sure.• He's the hardest man to get out, that's for sure.• International business man, that's for sure.• Sanders also ain't gonna like it, that's for sure.• They'd have to move to a smaller house, that's for sure.• It was not the breathing of a seventeen-year-old, that's for sure, but something more sonorous. 