sigh I'm so sorry, I'm gonna ask for another manga. Uhhm, this manga i dont really remember,but i remember some of the main scenes.I'm not really sure about the beginning and all but I'll try my best to sum it up.But first,let me tell you guys the things i remember:

*The girl liked her older sister's boyfriend for 11 years.
*The girl's older sister's boyfriend turns out to be her new sensei.
*So the teacher is super-handsome and popular.
*The girl student is simple, and [from what i remember] the girl gets tutored by her sensei.
*The girl thinks the sensei only sees her as a student and not as a woman.
*When they take a test, the girl gets angry and she takes her test and scribbles "Call my name" and runs away.
*The sensei then goes away to follow the girl and tells her that he wants her to graduate so that they can be together on stage and side by side [i think?]

I'm sorry if the way i detail this is retarded :/
&& also, if you could recommend, or give me a thread of mangas where its a student/teacher relationship,or a human/devil relationship i would really appreciate this.thank you!

It's Tsuyogari (FUJIWARA Kiyo) . ^^