Get $100 identifying this movie

[SuperHero]

I'll pay him/her $100 if anyone can identify this movie and can manage a copy (optional, and I'll pay extra charge for that) for me. I can pay via PayPal, skrills, phyza, liberty reserve, credit/debit card payment or whatever you want.

I am from Bangladesh. In my childhood around 1987-1992 in our country's govt TV channel showed a Chinese movie which I still remember and wanna see again. But I don't know the name of the movie. I only can explain the movie story now since I still remember it. In my childhood I couldn't differ was it Chinese movie or Japanese movie or Korean movie since I was little then and I found similarities in Chinese, Japanese and Korean people. But most probably it was Chinese movie.

Here is the movie story:

In a festival many people were showing many types of events on and beside a lake. The hero was showing a diving into the lake water. In his one diving he doesn't return from under the water. He goes to a underground world like a dream world. There he fall in love with a beutiful girl. They talk romantically beside lotus flower where were stones and flowing water. Finally once the hero find a way to get out of that underground world. And when he came out through a tunnel he found himself on top of a hill where the tunnel ends and he came out in daylight. From there he start to go to home but the underground people start to run behind him to take him back to the underground. But somehow finally he reaches his home and the underground people return. The girl was with him or not while coming home - I forget.

[SuperHero]

none able to identify it?