YOU SAID:

Mother has a daughter that gets married to the brother of the father of my dad

INTO JAPANESE

母には私の父の父の兄弟と結婚する娘がいます

BACK INTO ENGLISH

my mother has a daughter who will marry my father's father's brother

INTO JAPANESE

私の母には父の父の兄弟と結婚する娘がいます

BACK INTO ENGLISH

my mother has a daughter who marries her father's father's brother

INTO JAPANESE

私の母には、父の父の兄弟と結婚する娘がいます

BACK INTO ENGLISH

My mother has a daughter who marries her father's father's brother

INTO JAPANESE

私の母には、父の父の兄弟と結婚する娘がいます

BACK INTO ENGLISH

My mother has a daughter who marries her father's father's brother