GbEng
他的决心开始动摇了 His resolve began to waver.
但这并没有使他们动摇或退缩。 But this did not make them waver or retreat.
一旦下了决心，他就毫不动摇。 Once he's made up his mind, he never budges.
什么也动摇不了他要当律师的决心。 Nothing can weaken his resolve to become a lawyer.
他一旦下了决心就毫不动摇[无法使他改变（意见）]. Once he's made up his mind, he never budges/you can never budge him (from his opinion).