People can think a lot of things, that doesn’t make them true or even possible.
God is eternal, has perfect knowledge of all eventualities (past, present and future) and knows you exponentially better than you know yourself.
You have no idea even where to start to challenge him that he couldn’t have already put into your mind all kinds of attractive ideas to throw you off the track, if he so chooses to. You wouldn’t even know if the ideas were truly your own or so overwhelmingly convincing that you would have to accept them because they would be far better than any you could come up with on your own.
Do you even know or understand your own subconsciousness to the extent that you clearly grasp how your deeply held ideas arise or where the motives of credibility you have come from?
How about starting by challenging yourself to fully grasp why you believe the things you do and if you have sufficient warrant to believe all of those things?
Even that may be far more difficult than you suppose.