as sure as nails

例句：

1. 1.I am as sure as the sun rises in the east.
   我像太阳从东方升起一样确定。
2. 2. He was as sure of his answer as if he had been asked directly.
   他对答案的确信程度就像直接被问到一样。
3. 3. The scientist was as sure of her findings as if she had conducted a thorough experiment.
   这位科学家对她的发现深信不疑，就像她进行了一次彻底的实验一样。