I believe that the initial trust we have in the story-teller makes a deeper imprint than any eventual disappointment. And so, as readers and listeners, we instinctively trust the narrator; it's in our nature. At the very least, we go into a story assuming we can trust her until she gives us a clear reason not to.
To take it a step further, I believe we want to trust the narrator; that it taps into a place in us we may have lost, that we open a book already seeking a storyteller in control.
Try to See Things My Way, in The Art of Perspective: Who Tells the Story, Christopher Castellani