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
Meginfrid	-	Ancient Germanic
Hiltraud	HIL-trowt	German
Valentyna	-	Ukrainian
Evaline	-	English
Gretchen	GRET-khen (German), GRECH-ən (English)	German, English
EulÁLia	-	Portuguese, Hungarian, Slovak