sure of oneself

sure of (oneself)

Very self-confident. You can't go into that interview wondering if you're good enough for the job—if you're sure of yourself, the interviewer will be sure of you, too. A: "Well, Tammy's very sure of himself, isn't she?" B: "Yeah, we've never needed to worry about her succeeding in life."
See also: of, sure
Farlex Dictionary of Idioms.

sure of oneself

Self-confident, as in Now that Mary's graduated she's much more sure of herself. This expression uses sure in the sense of "confident" or "secure," a usage dating from the mid-1400s.
See also: of, sure
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • sure of (oneself)
  • sure of yourself
  • standing
  • cross (one's) t's
  • cross t's
  • sure
  • dot (one's) i's
  • dot i's
  • no matter how the dice fall
  • dot the i's and cross the t's
References in periodicals archive
Not coercing anyone to follow Him, Jesus asked: 'Do you also want to leave?' Peter personifies faith, a faith that is akin to love, as earlier noted, inasmuch as it is commitment and entrusting one's life completely to the other, because one is sure of the other, even as one may not be sure of oneself. 'To whom shall we go?
Words of Spirit and life
Being a warrior means being sure of oneself, having no uncertainty about one's own abilities or successfulness.
A dying breed
be sure whether one can be sure of oneself. Your body can tell when
Four from Dear Future Self
One always has something to learn in life and being too sure of oneself is a symptom of ignorance.
Defeating silence