New Revised Standard Version
This is the disciple who is testifying to these things and has written them, and we know that his testimony is true.

Contemporary English Version
This disciple is the one who told all of this. He wrote it, and we know he is telling the truth.

New American Bible
It is this disciple who testifies to these things and has written them, and we know that his testimony is true.

Douay-Rheims Bible
This is that disciple who giveth testimony of these things and hath written these things: and we know that his testimony is true.

This is that disciple who giveth testimony of these things and hath written these things: and we know that his testimony is true.

we know.

John 19:35 And he that saw it hath given testimony: and his testimony is true. And he knoweth that he saith true: that you also may believe.

1 John 1:1,2 That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon and our hands have handled, of the word of life. . . .

1 John 5:6 This is he that came by water and blood, Jesus Christ: not by water only but by water and blood. And it is the Spirit which testifieth that Christ is the truth.

3 John 1:12 To Demetrius, testimony is given by all, and by the truth itself: yea and we also give testimony. And thou knowest that our testimony is true.