Rennyuu Order The Animation (Series)

The protagonist, Takayuki, lives alone in Japan after being separated from his parents, who are away excavating in archaeological ruins in a distant country. One day, suddenly, Sasha, the princess of a mysterious country called Al-Fazhar and a cinnamon-skinned heroine, appears. She brings with her a letter from her father, which surprisingly reveals that Sasha has become Takayuki’s wife. Without wasting time, Sasha bewilders Takayuki by seeking the consummation of their marriage to conceive an heir and fulfill her marital duties. (Source: TMDB)