What is a sure sign which would confirm that you know Jesus?
Here's what John says, in 1 John 2:3-6.
And we can be sure that we know him if we obey his commandments. If someone claims, "I know God," but doesn't obey God's commandments, that person is a liar and is not living in the truth. But those who obey God's word truly show how completely they love him. That is how we know we are living in him. Those who say they live in God should live their lives as Jesus did.