People whose confidence rests upon the fact that they cannot imagine themselve being wrong, cannot adopt another point of view or stand being corrected or challenged, do not truly possess this attribute, but have only managed to delude themselves to a point where adopting any position of humbleness would destroy this important basis for happiness.
That just shows that their confidence rests on a very weak basis, since confidence that is built on strong foundations would never be so sensible as to not withstand challenge, nor depend upon any delusion of absolute certainty.