Class no Inkya Ojou-sama no Shitsuji ni Narimashita

When his family ran away and ditched him the middle of the night, he was saved by the introverted loner girl in his class! As he devotes himself to serving her as her butler, they gradually develop a bond, and the sad and lonely young lady's appearance and attitude begin to change...? This is a sweet, heartwarming romantic comedy, as the shy and clumsy young lady gradually grows up and becomes attracted to the well-mannered butler!

(Source: DLSite, translated)