Mairunovich

Kinoshita Mairu, is an unpopular high school student, who thinks she's ugly and plain. She is quickly transformed into a cute girl by the handsome and cool boy, Kumada Tenyu. She will search for real love while using her inner strength to change herself.
(Source: Translated of Hulu's official webpage)
~~ Adapted from the manga "Mairunovich" (マイルノビッチ) by Sato Zakuri (佐藤ざくり).