If you want to know if someone is "real" tell them an obvious lie. A human will recognize it for what it is immediately, a cursed will not. They may look real, but they are not. Only real eyes realize real lies.
My brother told me aliens and monsters lived under the bed.then the next morning I stuck my led off and hit the dog's leg and thought it was a monster's leg.from then on i would crawl to the end of the bed and take a flying leap out of my room :D