YOU SAID:

My aunty is my uncles wife and my grandpa is her mum

INTO JAPANESE

私の叔母は私の叔父の妻であり、私の祖父は彼女の母親です

BACK INTO ENGLISH

My aunt is my uncle's wife and my grandfather is her mother

INTO JAPANESE

私の叔母は私の叔父の妻であり、私の祖父は彼女の母親です

BACK INTO ENGLISH

My aunt is my uncle's wife and my grandfather is her mother