You still buying your govt propaganda. Will power did not help in 1988. And when a saturated missile strike comes your way, your will power will not do any good either. The only thing your will power could do is to shake your fist towards the sky and curse.
Their will power allowed them to deliver a decimating defeat to the French in Bien Dien Phu, the same will power allowed them to effect a psychological blow during the Tet Offensive. The same will power allowed them to reunify North and South Vietnam. The same will power enabled local militias to conduct a guerrilla warfare tactic against overwhelming Chinese military firepower in '79.
They (Vietnamese) are a small nation, but with the brevity of a tiger despite overwhelming odds.