1 Now faith is the assurance of things hoped for, the conviction of things not seen. Hebrews 11:1 (LSB)
Much of the false doctrine that we see in our time can be at least partially seen to emanate from a misunderstanding of what faith is. Paul tell us in Ephesians 2:8 that Christians are saved by grace through faith, and that not of ourselves, it is the gift of God. So, whatever faith is, saving faith has as its source something other than our fallen nature.
To understand what genuine saving faith is, let us take a deeper look at this something that has been made difficult to understand, but is actually quite simple. Faith is made up of three things: knowledge, belief, and trust. Knowledge always comes first.