1 John 3:19

And hereby we know that we are of the truth, and shall assure our hearts before him.
— 1 John 3:19, King James Version

In other translations

World English Bible (WEB)

And by this we know that we are of the truth, and persuade our hearts before him,

American Standard Version (ASV)

Hereby shall we know that we are of the truth, and shall assure our heart before him:

Young's Literal Translation (YLT)

and in this we know that of the truth we are, and before Him we shall assure our hearts,