Self-confidence is the most important type. It what allows a person to go towards his goal or goals in life. Usually when a person is confident to reach his goals, it means he trust his knowledge and his judgment in that topic. Being confident gives a person a push to go towards the goals of his life.
One thing that I recently discovered that a person should be fully insistence and sometimes stubborn in reaching his goals or he will have hard times in reaching his goals and he will almost be wasting many years of his life without trying to reach his goals even if they were clear and simple for him.
Having confidence in yourself is a great thing because it shows to others that you are really ready to do the thing that you want to do, such as, if a person wants to study even if he is older than his classmates in many years and he still shows up there, he goes to the lessons then he will learn new topics but if he did not have confident in his self then anything that could happen in the class will affect him such as if he answered a question in a wrong way, he might get disappointed by himself and he might thing others are criticizing him, but in reality when he has a strong personality it means he will be confident most of the times and he will go after the certificate he wants or his goal with OUT letting anything interfere with his decision or stops him from reaching his goals.