Confidence derives from the Latin fidere, "to trust." To be confident is to trust and have faith in the world. To be self-confident is to trust and have faith in oneself, and, in particular, in one’s ability to engage successfully or at least adequately with the world. A self-confident person is able to act on opportunities, take on new challenges, rise to difficult situations, engage with constructive criticism, and shoulder responsibility if and when things go wrong.
Self-confidence and self-esteem often go hand in hand, but they aren't one and the same thing. In particular, it is possible to be highly self-confident and yet to have profoundly low self-esteem, as is the case, for example, with many performers and celebrities, who are able to play to studios and galleries but then struggle behind the scenes. Esteem derives from the Latin aestimare [to appraise, value, rate, weigh, estimate], and self-esteem is our cognitive and, above all, emotional appraisal of our own worth. More than that, it is the matrix through which we think, feel, and act, and reflects and determines our relation to our self, to others, and to the world.
People with healthy self-esteem do not need to prop themselves up with externals such as income, status, or notoriety, or lean on crutches such as alcohol, drugs, or sex (when these things are a crutch). On the contrary, they treat themselves with respect and look after their health, community, and environment. They are able to invest themselves completely in projects and people because they have no fear of failure or rejection. Of course, like everybody, they suffer hurt and disappointment, but their setbacks neither damage nor diminish them. Owing to their resilience, they are open to people and possibilities, tolerant of risk, quick to joy and delight, and accepting and forgiving of others and themselves.
So what’s the secret to self-esteem? As I argue in Heaven and Hell, a book on the psychology of the emotions, many people find it easier to build their self-confidence than their self-esteem, and, conflating one with the other, end up with a long list of talents and achievements. Rather than facing up to the real issues, they hide, often their whole life long, behind their certificates and prizes. But as anyone who has been to university knows, a long list of talents and achievements is no substitute for healthy self-esteem. While these people work on their list in the hope that it might one day be long enough, they try to fill the emptiness inside them with externals such as status, income, possessions, and so on. Undermine their standing, criticize their home or car, and observe in their reaction that it is them that you undermine and criticize.
Similarly, it is no use trying to pump up the self-esteem of children (and, increasingly, adults) with empty, undeserved praise. The children are unlikely to be fooled, but may instead be held back from the sort of endeavour by which real self-esteem can grow. And what sort of endeavour is that? Whenever we live up to our dreams and promises, we can feel ourselves growing. Whenever we fail but know that we have given it our best, we can feel ourselves growing. Whenever we stand up for our values and face the consequences, we can feel ourselves growing. This is what growth depends on. Growth depends on living up to our ideals, not our parents’ ambitions for us, or the targets of the company we work for, or anything else that is not truly our own but, instead, a betrayal of ourselves.