确然

例句：

1. 1. I'm certain that you'll pass the exam.
   我确信你会通过考试。
2. 2. He certainly knows more about history than anyone else.
   他确实比任何人都更了解历史。
3. 3. We can't be certain of the outcome until we have more information.
   在获得更多信息之前，我们无法确定结果。