“吃了秤砣铁了心”英语怎么说？

Have been unshakable in self's determination by the sliding weight of a steelyard

to make up his mind...
to have decided definitely...
to have made the final decision...

decide to do
make one's mind to do

Lead Sails Paper Anchor
吃了秤砣铁了心，有一首歌就叫这个名字。

Eat a weight scale determined

Eat iron weight determined