I feel your pain. Us human's relationship between countries is no different than animals in a jungle. The big eat the small, the strong beat up the weak. China itself was bullied plenty by the "devils" from our east (you know, that country made up of short people), north (namely the northern bears), and west.
I just lied. We humans sometimes are actually smarter than animals. Instead of fighting my enemy directly, I'll lure and create an enemy for my enemy. It's called enemy's enemy. The Soviets "helped" Vietnam in order to contain China and fend off the U.S. Vietnam was like a little kid caught between the big bullies. The 1979 Sino Vietnam war was the latest collateral damage as a result of the games played between China, The Soviet and the U.S. Deng Xiaoping called The Soviet bluff and attacked Vietnam. The Soviet, as predicted by Deng, never dared to make a move. The result? Although China suffered a big casualty in the battle itself, it won a huge strategic war with The Soviet. Most importantly, the war allowed China to cozy up with America. Soon after the war China and the U.S. established formal relationship which triggered the spectacular economic growth for 30+ years. Vietnam was never in the conversation afterwards.
Now Vietnam is back on the world stage. You know why? Because India, Japan and uncle Sam want to play with China again
I wouldn't get too close to any of them if I were you. So far, every indication shows the Vietnamese leaders understand that very well. They have always been saying the right things, unlike the other small country in the region.
That sounds like what we are as well.