What is faith?

To have faith is to “hope for things which are not seen, which are true” (see Book of Mormon, Alma 32:21 and Hebrews 11:1). Each day you act upon things you hope for, even before you see the end result. This is similar to faith.
Faith in God is more than a theoretical belief in Him. To have faith in God is to trust Him, to have confidence in Him, and to be willing to act on your belief in Him. It is a principle of action and power.
The Book of Mormon prophet Alma compared faith to a seed. If you plant a seed and nourish it, if it is a good seed it will grow and eventually bear fruit (Alma 32:28-43). It is the same with faith. If you are obedient to God’s commandments, study His word, and have a desire to believe in Christ, faith will grow inside of you.

To me, Faith is a belief, a belief that causes action. Faith is greater than hope, it is greater than a belief, it is greater than a truth. It is a hope a belief and a truth, that causes you to act. For example to have faith in Jesus Christ, is to believe in Him, to know he was the true son of God, to hope you can be saved through Him, AND to follow and live his teachings. To act of your belief. As Alma portrays in Alma 32, as you begin to act, your seed will grow into a tree. Or in other words as you act on your beliefs, they will grow into a faith.