(Ephesians 4:17) “I declare and testify in the Lord that you must no longer live as the Gentiles do, in the futility of their minds.”
If someone is holding off believing in the LORD until they have the whole faith thing all figured out, then they are wasting their time in the futility of their minds. Faith is less about acquiring certainty in understanding and more about following the heart while living within the mystery of the unknowable.