be as hard as nails

to have no feelings or sympathy for other people She'll be good in business - she's as hard as nails.

Name	Pronounced	Usage
Mariella	mah-RYEL-lah	Italian
Wassa	-	Anglo-Saxon
Kimberly	['kimbəli]
Paki	-	Southern African, Xhosa
Peggy	['pegi]
Zef	ZEF	Dutch