It wasn't sudden

Well, with various things

Shy Satsuki Shinohara’s plan for a big high school debut are almost ruined by a pervert on the train, but she’s saved by none other than the “gangster” student in her class, Yamaguchi-kun. He’s already got a bad rap with the other students, and though Satsuki tries to approach him, he seems to always weasel out of her grasp. But she’s not one to let a challenge daunt her, and she’s out to prove that Yamaguchi-kun is so much more than he’s cracked up to be. <br><br>
(Source: Kodansha USA)