YOU SAID:
She sells sea shells on the sea shore. The shells that she sells are sea shells, I'm sure.
INTO JAPANESE
彼女は海岸で貝を販売しています。彼女が売っている貝は海の貝だと思います。
BACK INTO ENGLISH
She sells shells on the beach. I think the shells she sells are sea shells.
INTO JAPANESE
彼女はビーチで貝を売っています。彼女が売っている貝は海の貝だと思います。
BACK INTO ENGLISH
She sells shells on the beach. I think the shells she sells are sea shells.
That didn't even make that much sense in English.