Well, I'm not a JW, but I believe the once saved always saved idea is a false doctrine.
but Christ was faithful as a Son over His house whose house we are, if we hold fast our confidence and the boast of our hope firm until the end.
For in the case of those who have once been enlightened and have tasted of the heavenly gift and have been made partakers of the Holy Spirit, and have tasted the good word of God and the powers of the age to come, and then have fallen away, it is impossible to renew them again to repentance, since they again crucify to themselves the Son of God, and put Him to open shame. For ground that drinks the rain which often falls upon it and brings forth vegetation useful to those for whose sake it is also tilled, receives a blessing from God; but if it yields thorns and thistles, it is worthless and close to being cursed, and it ends up being burned.
Since therefore, brethren, we have confidence to enter the holy place by the blood of Jesus, by a new and living way which He inaugurated for us through the veil, that is, His flesh, and since we have a great priest over the house of God, let us draw near with a sincere heart in full assurance of faith, having our hearts sprinkled clean from an evil conscience and our bodies washed with pure water. Let us hold fast the confession of our hope without wavering, for He who promised is faithful; and let us consider how to stimulate one another to love and good deeds, not forsaking our own assembling together, as is the habit of some, but encouraging one another; and all the more, as you see the day drawing near. For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a certain terrifying expectation of judgment, and THE FURY OF A FIRE WHICH WILL CONSUME THE ADVERSARIES.