That is Hijiri Asukai from the S・L・H Stray Love Hearts manga! :D I just started reading it on manga here and I must say it is a must read!
On the eve of her sixteenth birthday, Kozue Hiyoki is visited in her dreams by a man who steals her heart- literally! Determined to find him and retrieve her stolen heart, Hiyoki enrolls in the S-Hall dormitories of St. Nazareth Academy, but quickly realizes that its residents are not at all like she expected... for starters, they are all guys.
Link to a safe site where you can read the manga;
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If you like that manga then you will also like Barajou no Kiss, it's by the same author the amazing Shouoto Aya!
Link to Barajou no Kiss manga;
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