Responses
Could it be
http://www.mangago.me/read-manga/koi_ga_moumoku_nara/
???
yes! this is the one! Thank you so much! ε=ε=(ノ≧∇≦)ノ
Do you know this shoujo, josei/harlequin manga? all I remember is that the guy needs to be married so that he will have a full authority for the boy (I don't know if he's his son or niece), so the girl helped him. there's this part where the girl accompanied the boy to buy some clothes but the girl said to buy the clothes that he wants.
Sorry for the grammar ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄