Kamen no Hanayome

Despite being born to a wealthy Greek family, Alesia lived a humble life with her mother after her ruthless grandfather banished them from the family. Then, for the first time in 15 years, Alesia is summoned by her grandfather only to be told he has chosen a man to whom she must marry. He demands she marry Sebastien Fiorukis, the eldest son of another wealthy Greek family. The two families have been feuding for two generations, so what could her grandfather be scheming? But if she accepts this proposal, her ill mother will be saved. Alesia reluctantly agrees, but she didn't know how her new fiancé would treat her...

(Source: Jmanga)