A book "Made in China" published in 1990s tells the story of a newly married couple who went on their honeymoon and then lost contact. The man lost his memory, and the man met him on the island.

Genius, I'm also looking for this film now! Do you have an answer?

When the man and his wife were hee hee at the seaside, they were beaten by the locals, knocked unconscious and put in the sea, and then drifted to an island, where a woman fell in love with him, and then. . . . . . . Finally, the man took the medicine of the local elders and his amnesia was cured.