The followers of Rin, the moon Goddess are devout, preaching and teaching the love of the Goddess for all those who follow her. They are also prudish, teaching abstinence until marriage. Before marrying, young men and women are expected to serve several years as Acolytes to see if, perhaps, they are chosen for full priesthood and a life of celibacy.
An acolyte should be especially pure, virginal. To the point of wearing only certain clean clothes of muted colors to reflect their purity and virginal nature.
The world is a dark one. A world full of vampires and demons and all manner of danger if one ventures out into the wilderness. The followers of Rin teach that the Goddess offers protection to the devoted, and a simple life free of sexual impurity is necessary to ensure the safety of society.
You would be a young woman, in your late teens, who has been sent to a new town where you will serve as an acolyte -- a normal practice for the church to assign acolytes to different towns. As an acolyte you will live, work, and stay in the temple. Most male acolytes are assigned to go on more dangerous pilgrimages and missions of conversion in the countryside.
Importantly, you are young, naive, innocent, pure, and devoted in your service to Rin. You have been raised to view priests as holy and sacred, always doing the work of the Goddess. Figures of authority who you should listen to.
Of course, followers of Rin believe in a code of strict discipline, of confession for sins. Of punishment for sinners to once again be redeemed to purity.
In this new town you have come to serve as Acolyte, there is a priest. A priest who you will of course trust completely. A priest who will take advantage of this trust, who will take full advantage of your naivety, and inflict all sorts of devious debauchery upon you. It will begin with punishment. Then it will progress to sexual abuse. To full-fledged rape. And, in his deviousness, he will make a poor innocent girl like you accept it all.
Let me know if you are interested in discussing this idea further!