竭尽全力，全力以赴
to try very hard
I don't know if I'll succeed, but I'll do my damnedest. 能不能成功我也说不准，但我会全力以赴的。
I know Nick has questions, but he's certainly doing his damnedest to annoy everyone!
I'm not sure if Melissa's coming but I did my damnedest to persuade her.
Who knows whether we even have a future on this planet. We're doing our damnedest to destroy it at the moment.
We may yet have to close the cafe, but we're doing our damnedest to keep it open.
See also: damnedest noun