YOU SAID:
I can’t believe you said that to my mother!
INTO JAPANESE
あなたが母にそんなことを言ったなんて信じられない!
BACK INTO ENGLISH
I can't believe you said that to your mother!
INTO JAPANESE
あなたがお母さんにそんなことを言ったなんて信じられない!
BACK INTO ENGLISH
I can't believe you said that to your mother!
That didn't even make that much sense in English.