Remember that Satan believes in God but has no faith or trust in anyone or anything but Satan.
To go from belief to faith is not a giant step but rather a realization that we already have faith in certain things in life. We go to start our car and we have faith that it will start. SOmetimes it does not and our faith gets shaken up a bit. But when we repair or maybe just tend to our car a little bit more, the faith comes back.
It is the same way with faith in God. Every time we try using our tiny bit of faith it becomes bigger and more powerful in our life. The trick here is to realize that if God does not “perform” at our desired level, He has a better plan for us.
So keep the faith and work on it. Our faith can grow into something beautiful indeed but it takes some effort on our part.