The Wallflower (Yamatonadeshiko Shichi Henge - Perfect Girl Evolution*)

Del Rey Book Description: "It’s a gorgeous, spacious mansion, and four handsome, fifteen-year-old friends are allowed to live in it for free! There’s only one condition–that within three years the guys must transform the owner’s wallflower niece into a lady befitting the palace in which they all live! How hard can it be? Enter Sunako Nakahara, the agoraphobic, horror-movie-loving, pockmark-faced, frizzy-haired, fashion-illiterate recluse who tends to break into explosive nosebleeds whenever she sees anyone attractive. This project is going to take more than our four heroes ever expected: it needs a miracle!"

*The literal translation of the Japanese title is "Perfect Girl Evolution". Yamato nadeshiko is a term meaning "woman who displays the feminine virtues of old Japan" [Japanese-English Dictionary] and henge is transformation. In Germany, Tokyopop holds the rights to the Deutsche language version of this series, and they have entitled it simply "Perfect Girl".