In that one verse the truth is pretty hard to miss.
It may seem hard to miss, but notice this verse is not an "offer" (which is the way most folks take this). It is a statement. Read it carefully and you will see Jesus is simply saying those who believe on Him will never perish. He does not say, "So, anyone interested?" He does not say, "And, anyone who wants to can come to Me." Actually, later in John (6:44 & 65) He says that no one CAN come unless the Father draws them and then absolutely every one of them will be saved.