Background (long version of the question)
Since the release of 105 hostages in December in exchange for a weeklong ceasefire, Israel and Hamas have not been able to reach a new deal that would enable the return of some or all of the 133 hostages Hamas is still holding.
In many news reports I have read about the negotiations for a new deal to release more hostages, it is stated that one of the main sticking points is Hamas's insistence that the deal should include a permanent ceasefire, and Israel's lack of agreement to that demand. For example, an April 8 Times of Israel article states (emphasis mine):
One Hamas official speaking on condition of anonymity to Reuters said negotiations have been at a deadlock due to Israel’s refusal to agree to a permanent ceasefire, the withdrawal of its forces from Gaza, the unrestricted return of all Palestinians to the northern Strip and the lifting of a 17-year-old blockade to allow speedy reconstruction of the coastal enclave.
This makes sense at one level: it seems understandable to me that Israel, having made the decision to eliminate Hamas as a force that threatens the security of its people, is unwilling to agree to a permanent ceasefire.
However, what I don't understand is this: all of these news reports seem to assume the basic premise that Israel must behave "honorably" in these negotiations in the sense that if it agrees to a permanent ceasefire, it cannot subsequently breach the agreement once the hostages are returned. But it seems like an obvious idea (which I have seen thrown around by various people in the Israeli media) for Israel to do whatever it takes to bring the hostages home, including possibly lying to Hamas about its future intentions. In fact, "ceasefires" are ephemeral by nature, and Hamas itself broke an existing ceasefire with Israel when it perpetrated its barbaric attack against Israel on October 7, 2023. Why then would it be wrong for Israel to break a hypothetical ceasefire after the hostages are safely home? Or if it isn't wrong, why is Israel seemingly going against its own interests by being completely transparent about its future intentions of destroying Hamas?
Another way of thinking about the issue is: will anyone seriously argue that it would be immoral or dishonorable for Israel to reach an agreement with Hamas that enables the hostages to be freed and then violate the agreement and continue to fight to destroy Hamas afterwards? Isn't any agreement reached under duress with a terrorist entity holding your people hostage unconscionable and null and void by its very nature?
From a moral perspective the issue seems clear to me. Say someone were to break into your house, kill a part of your family and kidnap one of your family members, and promise to do anything they can to kill more of your family members in the future. Say that this person then offers you a "deal" of getting your kidnapped family member back if you promise to not hurt them but instead give them a helicopter so they can escape. Isn't it obvious that you would be totally justified to go back on your word after your family member is released?
Moreover, if there is indeed a problem for Israel with "dishonorable" behavior such as violating agreements Israel makes with others, how can this be reconciled with Israel apparently having no problem with various other equally dishonorable behaviors? For example, Israel is believed to have carried out numerous assassinations on foreign soil, including on the territories of friendly countries, whose sovereignty it was bound to respect by international law and various diplomatic agreements.
The question (short version)
Why isn't Israel making a false promise to Hamas of a permanent ceasefire in order to reach a deal for the release of the hostages, with the intention of violating the agreement later?
A possible answer
One argument I can think of is that Israel, as a state actor who cares about its credibility in the world, cannot be seen to blatantly violate an agreement, even with a terrorist organization, since presumably that would make it difficult for it to be taken seriously by others when it wants to reach agreements with anyone in the future.
However, I'm not satisfied with this explanation. It seems to me that legitimate counterparties in future negotiations will understand that negotiations with a terrorist organization who is holding over 100 Israeli citizens hostage are not really analogous to an ordinary negotiation. Israel's credibility in the context of reaching agreement with legitimate states or organizations will not take a serious hit. It may be that going back on its agreement may make it difficult for Israel to reach deals with terrorist organizations in future hostage release negotiations. However, one would hope that Israel will never again find itself in a situation as terrible as the current one where so many of its citizens are held hostage. Again, the current situation is so extreme and unusual that I don't think the "loss of credibility" concern is sufficient to prevent Israel from using subterfuge and deceit to get its hostages back if that's what it will take. But clearly I'm missing something about why such a plan is not as simple to execute as I imagine it to be.