刀子嘴豆腐心

她雖然嘴巴毒，但其實是刀子嘴豆腐心。

Although she has a sharp tongue, she actually has a soft heart.

我媽就是典型的刀子嘴豆腐心。

My mom is a classic example of sharp tongue but soft heart.

別被他的話嚇到，他是刀子嘴豆腐心。

Don't be scared by his words - he has harsh words but a kind heart.