NET
35 And the person who saw it has testified (and his testimony is true, and he knows that he is telling the truth), so that you also may believe.
Darby
35 And he who saw it bears witness, and his witness is true, and he knows that he says true that ye also may believe.
KJV
35 And he that saw [it] bare record, and his record is true: and he knoweth that he saith true, that ye might believe.