We are born with a certain prevailing temperament:

There are four types of temperament:
1. Sanguine (optimistic, social, and associated with the element of air)
2. Melancholic (analytical, quiet, earth)
3. Choleric (short-tempered, irritable, fire)
4. Phlegmatic (relaxed, peaceful, water)

Some temperaments may appear to be stronger and therefore more confident.

Confidence is an action. When you were a little child you did not have the confidence to walk. After many tries and falls you have learned how to walk. Then you did not know how to lace up your shoes and your mom did for you, but then you learned how to do it.

If you want to develop confidence in a certain area just learn and practice to become confident at doing it. Confidence is not the same as perfection. You can do something confidently but not perfectly. For example, I was afraid to speak in public but after delivering 25 speeches I became confident at doing it. Now I can speak in front of a large audience.

I know people who are confident in business but lack confidence in romantic relationships. When they meet a woman they act like clueless geeks and cannot get anywhere with her. The reason for that is that they devote all their time to managing projects/people to achieve the bottom line by a deadline. Becoming confident in relationships requires different skills and practices: listening to and hearing your partner, studying what they like and do not like, and so on.

Accent reduction blog