Ousama To Fushigi No Shiro

From Chibi Manga:
A story about a sadistic main character!! A desperate and clumsy high school girl entered in a famous high school in order to be close to her “Prince”. But in fact, Hiroto is maybe a prince, but also a egotist and an arrogant man! But Mitsu is still in love of that Hiroto. Does Mitsu will be able get the heart of Hiroto who think she’s just a “parasite”?
from Sound of Jewels:
She entered in that expensive school because she wanted to meet the prince of this school.
But then she became his target and it looks like this boy is in fact really sadistic! What will she do…?