KUNMING, Jan. 10 (Xinhua) -- Tran Thi Vui, from Vietnam, runs a Pho Cuon (rice starch roll) restaurant in Hekou in southwest China's Yunnan Province. Just across a river -- and the border -- sits her hometown, Lao Cai.

Ten years ago, she fell for Bao Fusheng, a "diligent and honest" Chinese man. After they got married, the couple opened the restaurant, which became a hit among cross-border business people from the two countries.

"Vietnamese like bland flavor, while Chinese prefer spicy," said Tran, who, in order to cater to both tastes, adds Chinese spicy millet, garlic and soy sauce to the original Vietnamese fish and lemon dip.

A day's work begins at 4 a.m.: mixing fillings, grinding rice into rice milk, and steaming rice milk into skins. They sell an average of 400 to 500 rice starch rolls every day, and more than 1,000 during holidays.

Tran said that since business was booming, the two of them could no longer handle the increasing demand and have hired another five Vietnamese waitresses, three of whom have settled in Hekou.

Every morning, the two waitresses who still live in Lao Cai cross the China-Vietnam Nanxi River bridge and go through self-help customs clearance to work. In the evening, they go back home through the border.

"Traffic between the two countries has become more convenient, and the number of customers is growing," Tran said.

What she might not know is that over the years, China has become Vietnam's top source of tourists, while Vietnam has become China's eighth largest trade partner and ninth largest exporter.

The Second Lancang-Mekong Cooperation Leaders' Meeting was held in the Cambodian capital of Phnom Penh Wednesday. More concrete results are expected under the sub-regional cooperation mechanism jointly established in 2015 by the six countries along the Mekong River (known in China as the Lancang River), including China and Vietnam.

"The reason why the Lancang-Mekong cooperation mechanism has enjoyed rapid development is that the mechanism accords with the six nations' common willingness to enhance all-win cooperation and the trend of regional economic integration," Chinese Foreign Minister Wang Yi said. "It has shown strong vitality since it was born."

"I hope more people from China and Vietnam will have a chance to try my Pho Cuon," said Tran, who is considering expanding her restaurant and hiring more people.