Cho and her husband, Park Nam-gyu, in Cho's office at Hefei University. Zhu Lixin/China Daily

Half a year later, Park returned to Hefei University and has been there ever since.

Cho's brothers and sisters also brought their children to Hefei. "At the peak, I had 21 relatives living here, and there are still 12 of them now," Cho said.

Impressed by how the history teacher had influenced her son, Cho has encouraged Chinese students to go to South Korea. She has helped more than 3,000 students from Anhui to study in her country, and more than 1,000 were given job opportunities there. And she has brought even more students from South Korea to China.

To better promote the educational exchanges, Cho and her husband founded the Handa Cultural Exchange Co in Hefei in 2006, with Cho as president. Her son is general manager.

In 1998, when she was back in her hometown, Cho delivered a three-hour speech to 82 heads of primary schools, trying to persuade them to offer Chinese courses.

"China is developing very fast and will play more important roles in the world. The two countries must promote cooperation in many areas, but how can cooperation go well if our next generation doesn't understand Chinese?" Cho asked.

In 2000, with Cho's help, the Banyang Elementary School－in which she had studied－began teaching Chinese. It was the first primary school in the country to do so.

"Nowadays all the primary schools in my country have made Chinese-language courses available to students," said Cho, who was believed by some local media to have given the strongest push to the achievement.

Cho's reputation is not limited to education, however. It also extends to boosting Sino-South Korean economic ties and helping the province's poverty-stricken areas.

She also serves as an economic counselor for the Hefei Economic and Technological Development Area, where Hefei University is based, and the Hefei High-Tech Industry Development Zone.

Some of the South Korean companies based in the two zones, the largest in the province, were attracted through Cho's efforts.

She is now helping the development area build a China-South Korea Industry Park, and she has already brought in three South Korean companies to invest in the city's high-tech zone.

"Now I often accompany Hefei officials to South Korea for business recruitment and students for educational exchanges," Cho said. "In the early years, transportation between Hefei and South Korea was not convenient. Travelers had to change flights in Shanghai or Nanjing, Jiangsu province.

"There were even South Korean businessmen who intended to invest in Hefei but decided to invest in Shanghai and Nanjing instead, as they found the two cities to be more developed," she added. "Nowadays, flights connecting Hefei with Incheon in South Korea are available five days a week, and the situation is improving."

Cho and her husband have also donated hundreds of thousands of yuan to help prevent the children of poverty-stricken rural families in Anhui from dropping out of school.

The latest example was a 2016 donation of 20,000 yuan ($3,000) to four high school graduates in Hefei's Feidong county who had been enrolled at universities but were about to give up for lack of money.

Cho said the number of the poverty-stricken students is declining, and they can now get more financial support from the government, rather than relying on occasional social donations.

"In the five years since the 18th CPC National Congress in 2012, China has invested more than ever before in poverty relief, and President Xi Jinping has vowed to eliminate poverty by 2020," Cho noted.

"In the past 21 years, I have witnessed great development achievements in China, and I believe the five years to come after the pending 19th CPC National Congress will bring the country a more prosperous future."