an iron hand in a velvet glove

US /æn ˈaɪərn hænd ɪn ə ˈvelvɪt ɡlʌv/
UK /æn ˈaɪərn hænd ɪn ə ˈvelvɪt ɡlʌv/
"an iron hand in a velvet glove" picture
1.

tangan besi dalam sarung tangan beludru

a person who is outwardly gentle but inwardly firm and unyielding

:
The new manager has an iron hand in a velvet glove; she's polite but gets things done.
Manajer baru memiliki tangan besi dalam sarung tangan beludru; dia sopan tapi menyelesaikan pekerjaan.
Despite his gentle demeanor, the CEO ruled the company with an iron hand in a velvet glove.
Meskipun sikapnya lembut, CEO memerintah perusahaan dengan tangan besi dalam sarung tangan beludru.