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
Rigantona	-	Celtic Mythology
Awstin	OW-stin	Welsh
Kilikina	-	Hawaiian
Iago	ee-A-gaw (Welsh, Galician), ee-AH-go (English)	Welsh, Galician, Portuguese
Halima	-	Arabic
Agatha	['ægəθə]