Which theme does the story of cupid and psyche convey?

The theme of the story between psyche and cupid is that you should not let other people weaken your confidence in the one you love and who loves you back.

This is because, summing up the story, although it was the most beautiful of the three sisters, Psyche was the only one yet to be married, and her parents began to suspect that her daughter's beauty could have infuriated the gods. Thus, they decide to consult the oracle of Apollo and receive the news that the girl would not marry a human, but rather with a species of terrible dragon that lived on the top of a mountain.

The poor girl, accepting her fate, dresses in funeral clothes and decides to meet the creature. Psyche ends up going into a completely dark room and giving himself over to the monster. In time, the girl begins to enjoy encounters with the supposed dragon, but he forbids her from using any source of light and makes her promise that she will never try to see him.

And things between the two work wonders - until the sisters of Psyche appear for a little visit and, feeling jealous of how the girl lived, convince the young woman that she should finish the romance with the monster, find out his true identity and kill him. So one night, while the creature slept, Psyche, armed with a dagger, decides to light a lamp and discovers that, in fact, her husband is Cupid.  Surprised to realize that instead of being married to a horrendous being, her companion was one of the most beautiful creatures Psyche had ever seen, she walks away and ends up wounding herself with one of Cupid's arrows and falling madly in love with him. Then she accidentally knocks some of the hot oil from the lamp on the winged boy and he flees flying.

there is no poster. if you add a poster then we can answer.

the power of