Who is it that overcomes the world? Only the one who believes that Jesus is the Son of God. (NIV)
Who is it that is victorious over [that conquers] the world but he who believes that Jesus is the Son of God [who adheres to, trusts in, and relies on that fact]? (AMP)
Who is he that overcometh the world, but he that believeth that Jesus is the Son of God? (KJV)