hold (one's) nerve
To remain calm, steady, and resolute, especially in the face of danger or adversity. I know learning to drive can be daunting, but if you can hold your nerve out on the road, you'll do just fine. Wow, how did you hold your nerve speaking in front of the entire school like that? We can't turn back now, so hold your nerve and keep climbing up!
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.