I have an apple in my hand.
Now, do I really have an apple in my hand? You can't know for sure until I show you my hand holding an apple, right? You might take my word for it, but that's only because it really doesn't impact you very much. But you sure wouldn't be willing to bet your life on it until I showed you an apple inside my hand.
Now what if I told you this apple was in fact Omniscient and outside the bounds of time and space?
Would you take my word for it?