Definitely or positively (`sure' is sometimes used informally for `surely'):
— They are coming, for certain.

synonyms: certainly, for sure, sure, sure as shooting, sure enough, surely.

Roget 474: certainly etc. adj.; for certain, certes [Lat.], sure, no doubt, doubtless, and no mistake, flagrante delicto [Lat.], sure enough, to be sure, of course, as a matter of course, a coup sur, to a certainty; in truth etc. (truly) 494; at any rate, at all events; without fail; coute que coute [Fr.], coute qu'il coute [Fr.]; whatever may happen, if the worst come to the worst; come what may, happen what may, come what will; sink or swim; rain or shine.    ... show more