From Longman Dictionary of Contemporary Englishsuresure1 /ʃɔː $ ʃʊr/ ●●● S1 W1 adjective 1 certain you know something [not before noun]SURE confident that you know something or that something is true or correct SYN certain ‘That’s Sarah’s cousin.’ ‘Are you sure?’ ‘What time does the show start?’ ‘I’m not sure.’sure (that) I’m sure there’s a logical explanation for all this. Are you sure that you know how to get there? My mother, I felt sure, had not met him before.not sure how/where/when etc Henry wasn’t sure how to answer this.not sure if/whether I’m not sure if I’m pronouncing this correctly.sure of He wasn’t even sure of his mother’s name. They were talking about her, she was sure of that.sure about ‘That’s the man I saw in the building last night.’ ‘Are you quite sure (=completely sure) about that?’RegisterIn writing, people often prefer to use certain rather than sure, because it sounds more formal:We cannot be certain what causes this phenomenon.2 → make sure3 certain about your feelings [not before noun] certain about what you feel, want, like etcsure (that) Are you sure you really want a divorce?sure of Carla says she is very sure of her love for Tony.4 certain to be trueCERTAINLY/DEFINITELY certain to be trueone thing is (for) sure One thing’s for sure, we’ll never be able to move this furniture on our own.sure sign/indication Those black clouds are a sure sign of rain.5 certain to happen/succeedCERTAINLY/DEFINITELY certain to happen, succeed, or have a particular resultsure to do something He’s sure to get nervous and say something stupid.sure way to do something/of doing something There was only one sure way of finding out – and that was to visit him.sure thing/bet American English (=something that will definitely happen, win, succeed etc)6 → be sure of (doing) something7 → sure of yourself8 → be sure to do something9 → for sure10 → sure thing11 → to be sure12 → (as) sure as hell13 → have a sure hold/footing —sureness noun [uncountable]COLLOCATIONSadverbsquite sureAre you quite sure she won’t mind?pretty sureI’m pretty sure it was the same woman who called the office last week.absolutely sureDon’t throw anything away until you are absolutely sure you won’t need it again.not quite/entirely sure‘What are they?’ ‘I’m not entirely sure.’not exactly sureI’m not exactly sure when the funeral is.not very/too sureMake a list of any words or phrases whose meaning you are not too sure about.not at all sureBy now, we were not at all sure where we were. THESAURUSsure adjective believing that something is definitely true or correctI’m sure that you’re right.‘The car was a BMW.’ ‘Are you sure?’I’m not sure what the best thing to do is.certain adjective completely sure. Certain is more formal than sure, and it is very commonly used in writingThe police were certain that they had found the killer.I think he’s married, but I’m not certain about it.convinced adjective sure that something is true, even though you cannot prove itShe became convinced that her boyfriend was seeing someone else.Brown’s wife was convinced of his innocence.positive adjective especially spoken completely sure that something is true, especially when other people are not sureShe said she was positive that the exam was next Tuesday.I’m absolutely positive I haven’t made a mistake.satisfied adjective sure that you know the truth about something that has happened, because you have enough informationThe authorities are now satisfied that her death was an accident.confident adjective sure that something good will happen or that you will achieve somethingDoctors are confident that he’ll make a full recovery.A spokesman said the government was confident of winning the vote.have no doubt (also be in no doubt) v phrase to have no doubts in your mind about somethingI have no doubt that his story is true.He was in no doubt about what he should do next.know verb to have a strong feeling that something is true or correctI just know that she will love this necklace.When the phone rang, we knew something terrible must have happened.
Examples from the Corpus
sure• 'The car was a BMW' 'Are you sure?'• Lou Rigatoni laughed and doffed his hat, which Madame Astarti thought was a fedora but wasn't sure.• I think Leah lives here, but I'm not sure.• We do not believe this is the body of the missing girl, but we have to check to be absolutely sure.• I think children are influenced by these films, but it's impossible to be sure about this.• I'm pretty sure Barbara still works here.• Clara waited, eyes on the window, until she was sure Cybil was through with the Wedding March.• To be sure, designers on one side may pirate good ideas, may imitate design features, from the other side.• He wanted to be sure he could return to London if he didn't like his new job.• You need to be sure of your facts before making any accusations.• I'm surprised she isn't here - I was sure she would come.• Moreover, how could he be sure Sir Philip would disregard his illegitimacy, as Madeleine appeared to do?• Are you quite sure that he understood your instructions?• Are you sure that isn't Transylvania?• This is where you attract the patrons and sponsors who will make sure that you get the choice assignments.• Are you sure you aren't paying too much tax?quite sure• He wasn't quite sure how to treat Emily.• Doak is quite sure that dolphins have varied personalities or behavioural traits, despite the uniformity of their bodies.• Her only problem now was how to face Felipe, because she was quite sure that he would not be embarrassed.• If the fingerprints do match, however, then Y can be quite sure that the digital signature is authentic.• I feel quite sure the Black Agency would not approve.• No one in the room was quite sure what would happen next as Romanov offered no opinion.• We might as well take our time and make quite sure where we'd like to have them.• He was not quite sure who it was, but he had certain ideas.sure (that)• The taste suggests its Shirley Temple-ish hue is due to a splash of cranberry, though we're not sure.• They are friends and sometime lovers, but they are never sure how the other fits into their plans.• I was so sure I knew what was right, so critical of other people.• Owen was not sure that whatever lesson Osman had learned had been quite the right one.• I am sure they don't know this reality.• Everyone in the room remained seated, not quite sure what to do next.• We might as well take our time and make quite sure where we'd like to have them.• Researchers are not sure why Melanotan-2 caused such a reaction.sure sign/indication• The beginning of sugaring is a much surer sign of spring than is Punxsutawney Phil.• Auntie Ying says, and the sure sign of the eclipse of self is the loss of the power to tell one.• He scratched his head, a sure sign of thought.• It was thus a sure sign that his thoughts were far away.• The oyster boats were still fixed to the moorings, a sure sign that Oystermouth was in mourning.• It was still in place, a sure sign that the door had not been opened while he was out.• This is a sure sign that they need more practice.sure thing/bet• Elbert cautioned, however, that funding is far from a sure thing.• In either case, the outcome is pretty much a sure thing.• As Patrick O'Brien proved, maritime adventures are always a sure bet for landlubber readers.• That is far from a sure thing, however.• The only sure thing in Iowa is that nothing is sure.• At 38, he seemed a sure bet to become a towering figure of popular music.• They wanted instant access, just to make sure things were in place.• Our idea was that at last we could have a real go at it, make sure things worked out.suresure2 ●●● S1 adverb 1 → sure enough2 yes spokenYES used to say ‘yes’ to someone ‘Can you give me a ride to work tomorrow?’ ‘Sure.’3 accept thanks American English spokenTHANK used as a reply when you accept thanks from someone ‘Thanks for your help, Karen.’ ‘Sure.’4 emphasize American English informalVERY used to emphasize a statement It sure is hot out here. I sure hope they get there all right.5 before statement spokenTRUE used at the beginning of a statement admitting that something is true, especially before adding something very different Sure Joey’s happy now, but will it last?Examples from the Corpus
sure• "The turkey looks pretty good, doesn't it?" "It sure does."• And sure enough, the signatures did look personalized.• Sure, he's cute, but I'm still not interested.Origin sure1 (1300-1400) Old French sur, from Latin securus; → SECURE1 