My mother's best friend (Hilda) was a very old-fashioned Methodist born in about 1903. She was a genuinely holy woman who suffered many disappointments and heartbreaks in life but her faith in her Savior and mine (and yours) never wavered. She was personally charitable to a fault, a treasure for many years to her pastors who could count on Hilda for any effort consistent with the will of God.
When her longtime urban neighborhood had degenerated into a drug market and shooting gallery, she held on until her family insisted that she move to the suburbs. At that point, she could not find a Methodist Church to attend that was not an attack on her Savior and our civilization. From that point on, Hilda spent many hours in her living room with the Holy Word of God (KJV).
I am certainly a Catholic and a sinner and shall be fortunate to find myself in heaven. If I get there, I cannot imagine that Hilda and a lot of other holy Reformed Christians of my acquaintance would not be waiting for me if I am fortunate enough to arrive.
OTOH, a non-Catholic who has accepted Jesus Christ as his or her Savior and later commits terrible sins and dies unrepentant is in great eternal jeopardy. And it is not intellectually honest to say that such circumstances prove insincerity of the earlier acceptance of Jesus Christ by such a sinner.
You may disagree and you may have the last word. I have stopped wanting religious arguments here.
May God bless you and yours!
Anyone who CLAIMS to have accepted Christ and goes on to live in terrible sin, was very likely not genuinely saved to begin with and I don't know of any born again believer who would think that person had been.
If you are genuinely saved, you won't do it. Almost to the point of you CAN'T do it.
To sin and live under the conviction of God about it is pure misery.