Physically secure and certain, non-failing, reliable.
"The old bridge felt sure beneath our heavy boots as we crossed the narrow span over the rushing river."
In plain English: When something is sure, it will definitely happen without any doubt.
"I am sure that he will arrive on time."
Usage: Use sure to describe something that will definitely happen or is completely safe without risk of failure. It often replaces synonyms like certain when emphasizing reliability rather than just probability.
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"
Without doubt, certainly.
"I am sure that we will finish the project on time."
In plain English: Sure means doing something with complete confidence and without any doubt.
"Sure enough, the bus arrived right on time."
Yes, expressing noncommittal agreement or consent.
"Sure, I'll take that coffee break whenever you are ready to go."
The word "sure" comes from Middle French and Latin, where it originally meant "secure" or literally "carefree." It entered English with this same sense of being free from worry.