--Confidence is generally described as a state of being certain, either that a hypothesis or prediction is correct, or that a chosen course of action is the best or most effective given the circumstances.
Confidence can be described as a subjective, emotional state of mind, but is also represented statistically as a confidence level within which one may be certain that a hypothesis will either be rejected or deemed plausible. Self-confidence is having confidence in oneself when considering a capability. Overconfidence is having unmerited confidence--believing something or someone is capable when they are not.
Scientifically, a situation can only be judged after the aim has been achieved or not. Confidence can be a self-fulfilling prophecy, as those without it may fail or not try because they lack it, and those with it may succeed because they have it, rather than because of an innate ability.
Choking refers to losing confidence, especially self-confidence, just at the moment when it is needed most and doing poorly as a result e.g. in sports. This is found as a common plot device in literature and film, and is usually devised to result in a total alteration of a character's life.
"Confidence, like art, never comes from having all the answers; it comes from being open to all the questions."
-CL.
