Kodomo no Omocha

Sana Kurata, a child actress, faces many problems in her classroom, including a major one - her bullying classmate, Akito Hayama. Sana's outgoing and friendly nature leads her to work towards correcting all of the problems around her. Her 'meddling' irritates Hayama but at the same time captivates him, just as Hayama's gloomy nature irritates Sana and compels her to change him. As these two opposites attract each other, they face many hardships which bring them closer to a mutual understanding.

(Source: Anime News Network)