'Certain' in the Bible

Therefore, since we have now been justified [declared free of the guilt of sin] by His blood, [how much more certain is it that] we will be saved from the wrath of God through Him.

For if while we were enemies we were reconciled to God through the death of His Son, it is much more certain, having been reconciled, that we will be saved [from the consequences of sin] by His life [that is, we will be saved because Christ lives today].

For I testify about them that they have a certain enthusiasm for God, but not in accordance with [correct and vital] knowledge [about Him and His purposes].