The adv surely has 1 sense (first 1 from tagged texts)
1. (18) surely, certainly, sure, for sure, for certain, sure enough, sure as shooting -- (definitely or positively (`sure' is sometimes used informally for `surely'); "the results are surely encouraging"; "she certainly is a hard worker"; "it's going to be a good day for sure"; "they are coming, for certain"; "they thought he had been killed sure enough"; "he'll win sure as shooting"; "they sure smell good"; "sure he'll come")