What is the meaning of the phrase "if there is doubt as to whether penetration occurred or not - and this is unlikely"? And does this doubt remove the ḥadd (prescribed punishment) from the man who did not feel penetration due to clothing, and from the betrothed woman who sometimes confirms penetration and sometimes doubts it?

As for our statement, "This is unlikely," we mean that it is usually improbable for intromission to occur without both parties being aware of it and feeling it. Therefore, as long as he did not feel it, and she is in doubt and not certain of anything, then this is not considered zina (unlawful sexual intercourse), and the prescribed punishment (hadd) is certainly not obligatory for it. All that is incumbent upon them is sincere repentance, seeking forgiveness, blocking all pretexts, and closing off all avenues that could lead to such an occurrence again in the future.