Your history knowledge is not good.
1. After Vietnam defeated French and American, they considered themselves the 3rd strongest nation in the world following US and USSR, acted aggressively to all neighbors, they deployed troops in Cambodia, Laos, attacked China.
2. It's not that America offered diplomatic relations. America got hard struggle in Vietnam War, their dollar-golden system collapsed, they felt weak to face up Russian alone. It's Nikson who came to China for diplomatic.
3. China is founding country of UN and 1/5 of permanent member of security council since UN established in Oct. 1945.
Every year I can come across Pakistani people in China, they are polite and kind. In my opinion, as a normal person, I wish
Pakistan and India can keep peace.
Asia can become more prosperous.
Asia should't been the way it is today, Asia had most ancient civilization in the planet, but Asia is the most dangerous and poor continent nowadays.