be on (one's) mettle

To be determined to succeed and thus prove one's worth, often in a difficult or unpleasant situation. I know my employees think I'm too young to be their supervisor, so I have to be on my mettle every day at the office.

Common Names:

Name	Pronounced	Usage
'Iyyov	-	Biblical Hebrew
Jools	JOOLZ	English
Gillian	JIL-ee-ən, GIL-ee-ən	English
Kaiden	KAY-dən	English (Modern)
Angelina	ahn-je-LEE-nah (Italian), an-jə-LEEN-ə (English), ahn-GYE-lee-nah (Russian), ahn-gye-LEE-nah (Russian), ahn-gee-LEE-nah (Russian), ahn-ge-LEE-nah (Polish)	Italian, English, Russian, German, Dutch, Polish, Spanish, Macedonian
Kajsa	KIE-sah	Swedish