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English definition of “sure”

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sure

adjective
 
/ʃʊər/
A2 certain: I’m sure that he won’t mind. I’m sure about the second answer. →  Opposite unsure
make sure (that) A2 to take action so that you are certain that something happens, is true, etc.: Make sure that you close all the windows before you leave.
for sure B1 without any doubts: I think he’s from Korea but don’t know for sure.
be sure of something to be confident that something is true: He’ll win this year--I’m sure of it.
be sure of yourself to be confident of your own abilities, qualities, etc.: She seems a bit more sure of herself since she got a job.
(Definition of sure adjective from the Websters Essential Mini Dictionary © Cambridge University Press)
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