He came in for help after his attempts to stop smoking by willpower alone failed.

他仅靠毅力戒烟失败后到这里来求助。

《柯林斯英汉双解大词典》

For then we will realize that our lives are not controlled by the whims of fate, but by ourselves, by our own actions, and by our own willpower.

因为到那时我们就会意识到，我们的生活不是由莫测的命运控制的，而是由我们自己、我们自己的行动和我们自己的意志控制的。

youdao

Not by using my willpower, but by raising my awareness of what's more important to me.

不过，我不是在用我的意志力，而是让自己意识到哪些事对我来说才是更重要的。

youdao

The Dragon Boat Festival is a custom seemingly kept going by willpower, surrounded by the remains of a great tradition of endeavour.

BBC: Here be dragons

While some experts argue that people who are obese should simply eat less and exercise more, many physicians who treat obesity say it is driven by biological changes in the body, not lack of willpower.

WSJ: New Diet Pills Offer Option to Off-Label Obesity Drugs

When your brain detects a discrepancy, it reacts by throwing resources at it: attention, effort, deeper processing of information, and willpower.

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