Hey, I recommend you the book,"The Cold Wife Is Not Easy to Chase". This was a romantic youth-and-youth school novel. The male and female leads were both icebergs. The female lead was the eldest sister, while the male lead was a childhood sweetheart who had left the female lead for family reasons. The two of them met again by chance in university and began a beautiful love-hate story. The storyline is funny, sweet, and a misunderstanding. It fits your criteria. I hope you like my recommendation.😗
Pure love novels were novels with love as the theme. There were no commercial interests or political factors in the story, and the main story was about the love story between the protagonists. This type of novel was usually more romantic, sincere, and infectious. Here are some examples of pure love novels:
1 "How many flowers fall in my dreams"-Annie Baby
2. To Our Lost Youth-Xinyi Dock
Farewell My Concubine-Chen Kaige
4 "Alive"-Yu Hua
5 "White Night"-Keigo Higashino
"Your Name"-Makoto Shinkai
The above novels are all excellent pure love novels that can be read.
Well, one way this could work in a fanfiction is that Naruto could use Yuta's powers to enhance his combat abilities. Yuta has some really unique and powerful cursed energy techniques. Naruto might be able to combine his chakra with Yuta's powers, like using the Rasengan with Yuta's cursed energy for a super - powered attack. It could make for some really interesting battles against tough opponents like Madara or Kaguya.
It's hard to give an exact time as it depends on the manga's plot development. But typically, Yuta Okkotsu shows up when certain events and character arcs lead to his introduction.