Confidence comes from a Latin word 'fidere' which means "to trust"; therefore, having self-confidence is having trust in one's self. The concept of self-confidence is commonly defined as self-assurance in one's personal judgment, ability, power, etc. Self-confidence involves a positive belief that in the future, one can generally accomplish what one wishes to do. Self-confidence is not the same as self-esteem, which is an evaluation of one's own worth, whereas self-confidence is more specifically trust in one's ability to achieve some goal. Many LGBTQ+ people lack confidence because of ingrained and internalised beliefs, often instilled from childhood.
See: Affirmation & Belief.