Faith is a quality that many people confuse with being always good. However, it is not always good to have faith in a certain thing. For example, Hitler had very strong faith that the Jews were an inferior race and that they should be killed to make the world better. Hitler was a man of very strong faith, but it was faith in the wrong thing.
Many people accept that faith is both intellectual and emotional. Intellectually, it involves belief, and emotionally it involves trust. To have faith in a person is to trust them because of previous experiences, and it is to believe that they make correct decisions. If a person had complete faith in another, that person would allow the other to make all of their decisions for them without worry.
Faith does involve doubt at times, though. There will be times when you doubt a decision of faith. The decision may seem silly, but if your faith is in the right place, the decision will be right. Faith is formed over a period of time, through many experiences, sights and sounds. Faith may take a long time to come, but it can disappear very quickly. If you have faith in someone as a loving, caring person, and they suddenly begin to kill people, then you may lose faith in them quickly. However, the faith may come back again at a later time. This is because faith is a lifelong process, and it has high times and low times.
A person of strong faith may be someone devoted to a cause. If someone worked for years to collect books and raise money for a library, they probably had strong faith in the cause. It would be extremely hard to put forth all of that effort unless you had faith that you were doing the right thing.