prove (one's) mettle イディオム
mettle
mettle 1.
on one's mettle roused or prepared to do one's best
2.
on one's mettle roused or prepared to do one's best
prove (one's) mettle
To prove that one has ability and backbone of character, or the all-important skills, abilities, or ancestry to accomplish in something. You may be the youngest advocate in the firm, but you absolutely accepted your animation in that high-profile annihilation case. The new CEO accepted her animation by absolutely restructuring the dying adaptable buzz analysis into the assertive it is today.Learn more: mettle, prove
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