One reason could be for the sake of exploring different relationship dynamics. Fans want to see how Harry would react in a situation that is completely out of his control, like a forced marriage. It adds a new layer of drama to his character.
It could be a character from another important ninja clan, like Hinata perhaps. Since Hinata has always had feelings for Naruto and her clan is also a significant part of the village, Minato might see it as a good match.
It could be someone from a rival village. Maybe as part of a peace treaty, Naruto is forced to marry a kunoichi from a village that was once at war with Konoha. This would create a lot of tension and interesting storylines as Naruto has to deal with the cultural differences and the past hostilities between the two villages.
First, create interesting characters. Decide who the kidnapper is, their motives, and the personality of the kidnapped character. For example, the kidnapper could be a misunderstood noble who needs to marry to keep his title. Then, set the scene well. Describe the place where the kidnapping happens vividly.
Well, in such fanfiction, usually there is a strong sense of conflict. The kidnapped part creates immediate danger and high - stakes for the character. The forced - to - marry aspect often involves power dynamics. Maybe one character is from a powerful family or group that forces another into marriage, which can lead to a lot of emotional turmoil for the kidnapped character, like fear, anger, and a sense of helplessness.
A powerful and ancient magical being might force Harry to marry. This being could have its own motives that are not immediately clear. It could be related to some prophecy or an old magical law that only this being knows about. Harry would then have to figure out the nature of this being and how to persuade it to release him from the forced marriage.
One reason could be some sort of ancient magical law or prophecy. Maybe there's a hidden clause that says for the greater good of the wizarding world, they need to be married. It could be related to some power or protection that their union might bring.
"The Prince of Time Traversal Is Too Impatient." This was an ancient romance novel about a 26-year-old mature woman who transmigrated into a 13-year-old girl, and her life became a tragedy. She was the heir of the 108th generation of the Heiye family. Her medical skills and poison techniques were a piece of cake, and she was even better at disguising herself with martial arts. However, the emperor had decreed that she should be happy, and she had to face the harassment of the sick prince. As a fake wife, she still had to help her husband deal with all kinds of troublesome matters. In the end, the sunny and beautiful man and the golden-masked man suddenly appeared.
There are indeed such fanfictions. Some explore really interesting concepts within this odd scenario. For example, in some stories, the forced marriage is a part of a dark plot by Voldemort to gain more power over the wizarding world through Harry. Others might focus on how Harry copes with this situation and tries to find a way out while also dealing with his complex feelings towards Voldemort. It's a very unique concept that can lead to some very creative storytelling.
I'm not sure specifically which 'Forced to Marry the Billionaire' story you mean. There could be many novels or tales with such a title. Generally, in such a story, it might involve a situation where the protagonist is compelled to marry a billionaire perhaps due to family debts, business arrangements, or some kind of blackmail. Without more context, it's hard to tell the exact full story.