The theme of acceptance is also prevalent. Juvia may have to accept her new feelings, even if they go against what others expect of her or what she expected of herself. And she also has to deal with the acceptance or rejection from the person she loves, which can be a very emotional journey in these fanfictions.
One 'juvia loves someone else fanfiction' I know is 'Juvia's New Love'. In this story, Juvia falls for a mysterious newcomer in the town. It shows a different side of her character as she struggles with her new feelings while still having memories of her past relationships. The story has some really interesting dialogues that make you feel for Juvia's conflict.
I'd recommend 'Forsaken Hearts'. In it, the hero has an intense love for a person outside the main romantic pairing, creating tension and drama throughout the story.
One popular 'gray loves juvia fanfiction' is 'Frozen Hearts Thaw'. It beautifully portrays Gray's growing feelings for Juvia in a detailed and emotional way. The story delves deep into their relationship, showing how they overcome various obstacles together. It has some really heart - warming scenes that fans of the couple will surely love.
You can try fanfiction.net. It has a vast collection of fanfictions from various fandoms, and there's a good chance you'll find some great 'natsu loves juvia' ones there. Another place is Archive of Our Own (AO3). It is known for its wide range of fan - created content and a great tagging system that can help you easily locate the specific fanfiction you're looking for.
There's a fanfiction called 'The Unseen Bond'. It focuses on how Natsu and Juvia start to have a special connection that is initially unnoticed by the others in the guild. It slowly builds up the relationship with some really sweet moments. Also, 'Flame and Rain' is interesting. Here, their opposing elements of fire and water are used as a metaphor for their relationship, which is full of passion and contrast yet they manage to find love. Well, there's also 'Natsu's True Heart' which shows Natsu coming to terms with his feelings for Juvia after some misunderstandings.
Another option is Wattpad. There are many fans who post their 'gray loves juvia' fanfictions on there. You might need to do a bit more sifting through to find the really good ones, but it's definitely worth a look.
Maybe it's a powerful noblewoman from within the Seven Kingdoms. A woman who has been overlooked for marriage before but has her own influence and resources. Her marriage to Robert could be a way for her to gain more power and for Robert to gain more support within his own realm.