尽力而为

jìn lì ér wéi

to do what one can

Character by character

尽jìn
exhaust

力lì
strength

而ér
and

为wéi
act

我不敢保证成功，但一定尽力而为。

I can’t promise success, but I’ll do all I can.

Tone: neutral.

A polite promise that leaves room for failure; 为 is wéi.

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