YOU SAID:

she sells sea shells by the shore, but the sea shells that she sells are sea shells for sure

INTO JAPANESE

彼女は海岸で貝殻を売っていますが、売っている貝殻は確かに貝殻です

BACK INTO ENGLISH

She sells shells at the beach, but the shells sold are certainly shells

INTO JAPANESE

彼女は浜辺で貝殻を売っていますが、売った貝殻は確かに貝殻です

BACK INTO ENGLISH

She sells shells on the beach, but the shells sold are certainly shells

INTO JAPANESE

彼女は浜辺で貝殻を売っていますが、売った貝殻は確かに貝殻です

BACK INTO ENGLISH

She sells shells on the beach, but the shells sold are certainly shells