She might well force me to prove my mettle!
At 6 feet 1 inch and 235 pounds, he had proved his mettle.
Ed still has much to do to prove his mettle.
Of course, she had to go out into the world sometime and prove her mettle.
The two best contestants move to the final five while the rest will have to prove their mettle again.
When that force comes into being in December, it will quickly have to prove its mettle.
I will take on any challenger just to prove my mettle.
Maybe this meant that they wouldn't have to move into the field and kill people as frequently to prove their mettle.
Said he'd settle for a share of the inn, and a chance to prove his mettle when the time came.
Or he'll prove his mettle and they will accept him.
You had to show your mettle on the pitch, and only then would he open up.
With all you fit young men a doctor doesn't have much of a chance to show his mettle.
As for the politicians; at times like this it is that they show their mettle.
On the face of it, he showed his mettle in the boxing ring.
It was then that the stooped man showed his mettle.
With or without him, though, Carroll will have to show her mettle, in every sense of the word.
All of them had shown their mettle in previous engagements.
Steer will have to show its mettle to win contracts.
But he showed his mettle and now we love him.
"However, you and I must do some practicing so we'll show them our mettle."
Idiomy