Readers know the stories they read aren’t real but you have to make them believe that they could be.
As a reader yourself what makes you suspend belief as you get lost in the words and pages?
Is it a character that’s lifelike, someone like you, someone that you know?
Sometimes a reader will suspend belief if they can enter a story though a character they like and who is like them, has similar qualities to them even if the plot and setting seem far fetched.