There are cures. Those have nothing to do with the causes of fear. A cure is permanent. Dwell on the past victories and successes. Remind yourself of when you did it, not when you didn't.
Many people have fear and are clueless as to the cause.
Sometimes that self-discovery is enough to make it dissipate or disappear. I strongly recommend The Strangest Secret by Earl Nightingale. It's a 30-minute lesson about the reality of how you think about yourself. Recorded in the late 1950s, it is still the single most powerful personal development message available today. Here are a few more exercises you can perform to build your confidence to speak or present, and heal your fears.