Undoubtedly, this is the truth of certainty.
This is the absolute truth.
Indeed, this is the certain truth
Surely this is a certain truth
That truly that it is (E) true , the assurance/certainty
All this is absolute truth
This is indeed an utmost certainty
Verily, this is the certain truth
Assuredly, this is the absolute truth of certitude
Verily, this (fact) is a perfect certainty (not merely a certainty by inference or sight)
Verily, this! This is an absolute Truth with certainty