True. "Whosoever believeth in him, may not perish, but may have life everlasting". But that belief, in order to be authentic belief of the first Christians who knew Jesus in the flesh, must be the belief of the One Holy Catholic Church, the only one He founded and purchased with His blood, the pillar and ground of all truth.
For example, do you also believe that the Holy Eucharist is the window on the actual sacrifice of Christ at the Golgotha hill? And that the bread and wine of the Eucharist is the actual body and blood of Jesus Christ? Yet He also said that:
I am the living bread which came down from heaven. If any man eat of this bread, he shall live for ever; and the bread that I will give, is my flesh, for the life of the world. The Jews therefore strove among themselves, saying: How can this man give us his flesh to eat? Then Jesus said to them: Amen, amen I say unto you: Except you eat the flesh of the Son of man, and drink his blood, you shall not have life in you. He that eateth my flesh, and drinketh my blood, hath everlasting life: and I will raise him up in the last day. (John 6)
The Catholic Church believes this as written. You, too, if you want to believe Jesus Christ in full, need to read the Bible in full and believe all the Christ said, not only John 3:16, and then you will be Catholic (or Orthodox, who are essentially also Catholic).
arrogant people
It is not possible to proclaim an absolute truth and not sound "arrogant" to someone who has some private "truths". That is regrettable, but that is how it is.
Then why do you mess around with wafers and wine?
So to be consistent with the literal meaning, you must contend that unless one believes and receives the "Real Presence" then they have neither spiritual nor eternal life.