The Wayward Wish
At the moment, I'm simply brainstorming, as most of the finer details would need to be worked out. However...
I'm thinking in a fantasy setting, my character is an adventurer who discovers a magical artifact or stone that will grant him one wish. He wishes that he were the ruler of a great kingdom. The wish is granted in a flash of bright light.
The next morning, he awakens - now a princess on her arranged wedding day!
With no way to resist the prince/king (or great adventurer who has forged his own kingdom - your character) and the plans for the day - trapped forever in her new body - she has no choice but for the vows to be spoken, the ring to go on, the flowers to be given (the other women in attendance thought the wedding was SO romantic!), and to receive the ceremonial post-wedding virginal cunt-pummeling from her new husband!
We can discuss further specifics. If you're into pregnancy, then it can be too bad for her that he's so virile. A life of barefoot pregnancy awaits!
If you're interested, send a PM. Please do not reply here. Thank you!