Tanbo de Hirotta Onna Kishi, Inaka de Ore no Yome da to Omowarete Iru

Jin Mita, a farmer in the countryside, discovers a female knight lying in the rice paddy. When he asks the knight, who calls herself "Seraphim," about her story, it seems that she came from another world. The female knight, suddenly thrown into modern Japan, naturally has nowhere else to go, so Jin...

Source: MyAnimeList