In theatre, there's a phrase about what it takes for the audience to feel that what it's watching is real: the suspension of disbelief.
That is, the audience starts by disbelieving that the action in front of them is real, since they know it is staged. But gradually, as the audience gets drawn in to the setting, the characters, and the story, the play almost ceases to be artificial to them and can start to seem real. At that point the audience has suspended its disbelief, and believes what it sees.
Is growing in faith like that? Do we start off with an overly realist sense of the world, and gradually allow ourselves to suspend disbelief and accept what we say we believe in as real? Much of what we believe is invisible and abstract, and it isn't until we see it acted out in front of us that we start to suspend disbelief. And of course, one important difference is that unlike a play, what we believe in actually is real.