Examples
chú fēi除非tā他qīn kǒu亲口duì对wǒ我shuō说，fǒu zé否则wǒ我jué bù决不xiāng xìn相信。
除非他亲口对我说，否则我决不相信。
I will not believe it unless and until he tells me so.
决不放弃。
Never give up.
你怎么敢指责我做这种事？我决不会动手打我的儿子。
How can you accuse me of such a thing? I would never lay a hand on my child.