And it's a God given certainty.
Jesus Christ is God. Holy. He cannot lie.
'For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.
And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one.
If we receive the witness of men, the witness of God is greater: for this is the witness of God which he hath testified of his Son.
He that believeth on the Son of God hath the witness in himself: he that believeth not God hath made him a liar; because he believeth not the record that God gave of his Son.
And this is the record, that God hath given to us eternal life, and this life is in his Son.
He that hath the Son hath life; and he that hath not the Son of God hath not life.
These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God.'
1 John 5:7-13
'He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him.'
I KNOW where I'm going. How about you?