I am certain that I will pass the exam.

He has a certain charm that makes people like him.

I will make certain that the door is locked before leaving.

There are certain types of flowers that only bloom in the spring.

I can't say for certain whether the weather will improve this week.

I will certainly attend the meeting tomorrow.

I have complete certainty in my decision.

Despite the lack of evidence, she held a moral certainty that he was innocent.