I absolutely love this poem as well as the idea that Persephone was not, in fact, kidnapped, but instead willingly ate the pomegranate seeds to stay with Hades <- There was a version of the myth where she did just that.
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.