It depends. 'Smile' could be considered a realistic fiction book if it portrays real-life situations and characters in a believable way. But without knowing more about it, it's hard to say for sure.
The novels such as Silent Flute, Poisonous Concubine, Hua Qian Gu, Shanshan Lai Chi, Step by Step Startling Heart, Poisonous Concubine, Palace Heart Locking Jade, Step by Step Startling Heart, Special Agent Concubine: Reborn in the Modern Era, Special Agent Doctor: Useless Miss Seven, and so on had similar styles to A Smile Is Alluring.
Her smile was very alluring. The recommended novel that was similar to the slightly smiling and very beautiful genre was "The Beauty Is Not Crossing". It was about a girl named Yan Weinian who transmigrated to another world and began a story of ups and downs. I hope you like this fairy's recommendation. Muah ~😗
In the case of 'Smile the Book' fan fiction, it could potentially focus on the emotional aspects that the book evokes. Maybe it dives deeper into the backstories of the characters. Fan fiction authors might also play with the themes of the book in different ways, for example, if the book has a theme of friendship, the fan fiction could show different scenarios of how that friendship was formed or tested. It could also bring in new characters that interact with the existing ones in unique ways.
The date of publication of the book is still unknown. It is recommended to check the relevant publishing information or follow the novel website or social media account to get the latest information.