How shall Allah guide a people who disbelieved after their belief and after they bore witness that the Messenger (Muhammad ﷺ) is true and after clear proofs had come unto them? And Allah guides not the people who are Zalimun (polytheists and wrong-doers). They are those whose recompense is that on them (rests) the Curse of Allah, of the angels, and of all mankind. They will abide therein (Hell). Neither will their torment be lightened, nor will it be delayed or postponed (for a while).
[Aal 'Imraan 3:86-88].
And yet after all that, Allah, may He be glorified, says:
Except for those who repent after that and correct themselves. For indeed, Allah is Forgiving and Merciful.
[Aal 'Imraan 3:89].
Allah, may He be glorified and exalted, says (interpretation of the meaning):
Verily, those who disbelieved after their Belief and then went on increasing in their disbelief (i.e. disbelief in the Quran and in Prophet Muhammad ﷺ) - never will their repentance be accepted [because they repent only by their tongues and not from their hearts]. And they are those who are astray.
[Aal 'Imraan 3:90]
Question: In this verse 3:90, what constitutes an increase in disbelief?
If a person who was a Muslim commits shirk and becomes a murtad, then he regrets it and finds out that a murtad can come back to Islam so he repents and recites Kalima, but later he again apostates and becomes a murtad again, but later regrets it, he may feel that that repeated apostasy cannot be forgiven and feels hopeless. If after this, he commits kufr in his mind once again, then regrets it and repents. If he tries to follow Islam, will Allah forgive such a confused person, and can he enter Islam again?