Maḥabba: Love
Al-Ghazali places love at the end of the whole path, the thing every other practice was for. Someone who has just broken their own word braces for that subject to come up; being asked about love instead tells them they are still wanted. The question carries an edge too, since love counts as love only when nothing else is quietly kept ahead of it.
He loves them and they love Him: being loved comes first
The Quran puts God's love ahead of the person's, and the Sufis build everything on that order. The love being asked about started on the other side, placed in someone before they ever felt a thing. So even a person who has just proved how weak they are can answer without lying.
Ṣidq: Truthfulness
The term means keeping your claim level with what is in you. Big promises are what collapsed last time, so the smaller answer is the one that can be stood behind. Holding back the bigger word costs some pride, and it keeps a person inside what they can honestly sign for.
The heart is turned between two fingers of the Merciful: nobody can vouch for their own heart
A saying of the Prophet, who also prayed to the Turner of hearts to keep his own steady. Someone whose nerve has failed once knows their feelings can swing without warning, and that a fresh vow settles nothing. So the answer gets handed over to the one who can see them, which holds better than another promise.
Khidma: Service
Sufi houses have always measured love by who does the work: the cooking, the cleaning, the care of whoever arrived last. A question about love answered with a job puts the whole thing somewhere it can be checked. After that, the feeling matters less than whether the people put in their care are fed and looked after.