With this understanding, the terms Sanatan Dharma and Hinduism become interchangeable with an identical meaning. Just as there are Christians, for example, who are not from the Middle East, not Hebrew and do not speak Aramaic, there are Hindus of all races and nationalities. No one knows how old is Sanatan Dharma, and there is of course no one founder. A belief is something that may or may not be true.
Faith is assurance or a guarantee.
For example, for a long time it was believed that the earth was flat, now we have the assurance or faith in a round world. Obviously, the key to faith is experience . This is central to Hinduism. However, each one is encouraged to develop a solid faith grounded in experience. In other words, after a thorough testing of one's beliefs when arrives at the relaxed state of faith or assurance.