'Certainty' in the Bible

To cause thee to know the certainty of sayings of truth, To return sayings of truth to those sending thee.

I have drawn near unto one of those standing, and the certainty I seek from him of all this; and he hath said to me, yea, the interpretation of the things he hath caused me to know:

'Then I wished for certainty concerning the fourth beast, that was diverse from them all, fearful exceedingly; its teeth of iron, and its nails of brass, it hath devoured, it doth break small, and the remnant with its feet it hath trampled;