Definition of For sure

• definitely or positively (`sure is sometimes used informally for `surely); "the results are surely encouraging"; "she certainly is a hard worker"; "its going to be a good day for sure"; "they are coming, for certain"; "they thought he had been killed sure enough"; "hell win sure as shooting"; "they sure smell good"; "sure hell come"
• not open to doubt; "she wanted to go; that was for sure"