Responses
It's just a theory. But because she couldn't be with her prince, for some unknow reason, she took revenge on the villager by controlling their life and so on. But when the prince decided to go and meet with virgin(?), the goddess is freed from her attachment to earth and frees the island.
So I suppose she was maybe a ghost and that's why she made the people suffer because she could be happy, or because of her position she couldn't do what the villagers did when she was sleeping. So the "this should be your suffer alone" line (i think it's that), takes all its sense...but i'm not sure and it seems a bit unrealistic...
From what I could gather, some false goddess isolated an island from the rest of the world and removed everything she saw as "sin" from everyone's memories except for her chosen one and Helga, so everyone considered Helga as dirty and sinful because she remembered and still had worldly desires. I get that much, but what happened at the end, after Helga's so-called trial?