It Turns Out that I have a Fiancée, but She is the Famous "Villainess" of the School. What Should I Do?

A few days into the new school year, the life of Hiroyuki Higashikujo, an ordinary high school boy, is changed dramatically. Ayane Kiryu, a smart and beautiful young lady nicknamed “The Villainess,” is now...... his fiancee! They are two people with completely different family backgrounds, positions, and personalities. And then their friends and acquaintances will soon get involved… This is the start of an exciting coming-of-age story between two people who come to terms with their thoughts and feelings! (Source: NicoNico Seiga, translated)