Doubt!! - Izumi, Kaneyoshi

Ai Maekawa is a jimi—a homely, studious girl. After being horribly embarrassed by a popular student towards the end of middle school, Ai uses the break between middle and high school to carry out a complete makeover. Between dieting, makeup and new clothes, Ai makes herself into a beauty. Imbued with newfound confidence, she decides to pursue Sô Ichinose, the most handsome and popular boy in her class. Over the course of the series, Ai attempts to win and keep Sou's affections, as well as friends both female and male.

(Source: Wikipedia)

Doubt!! was published in English by VIZ Media from March 1, 2005 to January 10, 2006.