No, they never truly believed. Yes they made a public profession of faith and walked down the isle, but they were never inwardly converted.
1 John 2:19
They went out from us, but they were not of us; for if they had been of us, they would have continued with us; but they went out that they might be made manifest, that none of them were of us.
Ok so you think that 1 John 2:19 is saying that anyone who turns away was never a true believer? Because that’s not what is actually written in that passage and that interpretation directly contradicts James 5:19-20. So first of all John is talking about a specific group of people. “They went out from us” not “if anyone went out from us”. In that passage John is talking about a specific group of people who left the church. So let’s compare this to James 5:19-20.
“My brethren, if any among you strays from the truth and one turns him back, let him know that he who turns a sinner from the error of his way will save his soul from death and will cover a multitude of sins.”
James 5:19-20 NASB1995
Here James is talking about a true believer who strays from the truth of the gospel and says that his soul is in danger of death unless he is turned BACK. The key indicator that this person is a true believer is the phrase “and one turns him BACK”. If this person wasn’t a true believer to begin with he would have nothing to turn back to that would save his soul from death. Only a backslidden true believer can turn back and be saved. Now if what you’re saying is true and a true believer can’t lose their salvation then this person’s soul could never be in danger of death in the first place just like those who fail to abide in Christ in John 15:6. In fact John 15:6 would be describing an impossible scenario if it is impossible for someone to fail to remain in Christ to the point of being cast away to wither and cast into the fire to be burned since according to Calvinists no one can come to Christ unless The Father draws them. You don’t recognize that the means by which we are drawn to Christ has changed after His crucifixion according to John 12:32.
“And I, if I am lifted up from the earth, will draw all men to Myself.””
John 12:32 NASB1995
In John 6:44 Jesus was talking about how people were drawn to Him at that time. In John 12:32 Jesus is talking about how people will be drawn to Him after His crucifixion. There’s a definite change in the way that we are drawn to Christ after His crucifixion and it’s thru the gospel which is why the very last words He spoke to His apostles before ascending into heaven were….
“Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit, teaching them to observe all that I commanded you; and lo, I am with you always, even to the end of the age.””
Matthew 28:19-20 NASB1995
This is His plan for how He draws all men to Himself after He is raised up.
“For I am not ashamed of the gospel, for it is the power of God for salvation to everyone who believes, to the Jew first and also to the Greek. For in it the righteousness of God is revealed from faith to faith; as it is written, “But the righteous man shall live by faith.””
Romans 1:16-17 NASB1995
Notice that the gospel is the power of God for salvation for everyone who believes, not for those who are allowed or chosen to believe.