1 occurrence

'Certainly' in the Bible

And King David said to Ornan, No; I will certainly give you the full price for it, because I will not take for the Lord what is yours, or give a burned offering without payment.

Bible Theasaurus

Certainly (682 instances)
Surely (741 instances)

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain