"When reaching 40, one should no longer have any doubts," Confucius once said.

What he implied was that an individual who is 40 or older should feel confident: Bewilderment and the feeling of loss should not be a bother anymore.

More than 2,600 years on, Confucius would not have foreseen that his random thoughts about the correlation between lifespan and wisdom accumulation could be borrowed to guide diplomacy.

Wang Donghua, Chinese consul general in San Francisco, cited the Confucius saying Friday at a gathering of more than 800 people celebrating the 40th anniversary of the establishment of China-US diplomatic relations.

Wang gave his retrospective accounts of the inception and on the growth of the Sino-American relationship, as well as its challenges and opportunities.

The diplomat also shared his optimism at "a crucial moment" about the future of "one of the bilateral relations with greatest potential and influence in the world today".

"The China-US relationship is over 40 years old," Wang said. "The two sides should have more understanding and less misunderstanding, more trust and less doubt, and act more with reason and less on impulse," he continued, adding, "in this way, the relations between the two countries will be more stable, the cooperation more rewarding, and the two peoples more prosperous."

The audience included San Francisco Mayor London Breed, California Assembly Member Kansen Chu and California State Treasurer Fiona Ma, among others.

"Forty years ago, the older generation of leaders of China and the United States broke the ice of isolation between the two countries with extraordinary strategic vision and political wisdom and made a historic decision to establish diplomatic relations between the two countries," Wang said. "The establishment of China-US diplomatic relations has been having a huge and profound impact on the development of our bilateral relations and the maintenance of world peace."

Breed said that the four decades of relations have been "a time of growing exchanges and understanding".

"We have realized the great possibilities of cooperation between our two nations, and this anniversary is a chance to remember that we have an enormous stake in each other's success," she said. "In an interconnected world, countries would be more prosperous when we work together as one."

The mayor's words are accurate.

According to incomplete statistics from both governments, bilateral trade in goods surged to $633.5 billion in 2018, a more-than 260-fold increase compared with the figure of $2.45 billion in the 1980s. Bilateral trade in services, from zero in the early days, has grown to $75 billion in 2017.

Two-way investment exceeded $230 billion in cumulative terms in 2017. About 68,000 US-funded companies have been operating in China.

In 2016 only, American companies operating in China recorded total sales volume of $606.8 billion, surpassing their Chinese counterparts in the US by $400 billion.

Tourism and people-to-people exchanges flourished, too.

In 2017, more than 3 million Chinese visited the US, spending $33 billion during their stays. While about 20,000 American students are currently studying in China, more than 400,000 Chinese students are opting for American universities and colleges.

More importantly, China and the US have conducted cooperation and collaboration on international and regional issues of common concern such as anti-terrorism and non-proliferation, the international financial crisis, disease control and prevention, environmental protection, and lunar exploration.

China and the United States are important partners rather than strategic adversaries, Wang said. China-US cooperation is mutually beneficial instead of a zero-sum game.

The hard-won progress achieved in bilateral relations comes from the wisdom and hard work of generations of leaders and people of both countries and needs to be cherished and carefully nourished, he concluded.

Contact the writer at junechang@chinadailyusa.com