sb's bark is worse than his/her bite 刀子嘴豆腐心；言语比行动吓人

【例句】
He may seem very angry but don't worry his bark is worse than his bite.
他可能看起来很生气，但是别担心，他刀子嘴豆腐心。

Don't be scared of the supervisor. His bark is worse than his bite and he's really a nice guy.
不要怕那个主管，他刀子嘴豆腐心，他其实是个好人。