What do you mean by "absolute certainty"? If that means a mental state in which faith and hope are no longer necessary, I doubt that day will come in this life. As Paul wrote,
16 The Spirit itself beareth witness with our spirit, that we are the children of God:17 And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together.
18 For I reckon that the sufferings of this present time are not worthy to be compared with the glory which shall be revealed in us. (Romans 8:16-18)
The Spirit bears witness that I am a joint-heir with Christ. If I continue to suffer with Him, I will be glorified. I am as certain of that as I can be of anything.
However, I do not yet see the glory that I am to inherit. Until I do, I must wait with hope and patience:
24 For we are saved by hope: but hope that is seen is not hope: for what a man seeth, why doth he yet hope for?25 But if we hope for that we see not, then do we with patience wait for it. (Romans 8:24, 25)
You offer a strawman; not surprising: "If that means a mental state in which faith and hope are no longer necessary ..." First faith is not only necessary, it is THE GIFT OF GOD! I have a mental state that I am assured my Salvation rests not on my ability to prevent loss of redemption, rather I am absolutely mentally certain of Salvation because of God's promise. That is the Faith He places within you when you are born again! ... He is not a man that He should lie. When you are born again, you too will know that surety.