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
Julijana	-	Slovene, Croatian, Serbian, Macedonian
Esther	ES-tər (English, Dutch), es-TER (French)	English, French, Spanish, Dutch, German, Danish, Norwegian, Swedish, Jewish, Biblical, Biblical Lati
Winter	['wintə]
Yahui	-	Chinese
Gyneth	-	Literature
Elaine	i-LAYN (English)	English, Arthurian Romance