have nerves of steel字面意思有钢铁般的神经，引申为意志坚强，有胆量。

【例句】
You need to have nerves of steel= tobe very brave to be a fighter pilot.
当一名战斗机飞行员，你需要有过人胆量。

Entrepreneur has to have nerves of steel.
企业家需要意志坚强。