I think it’s pretty obvious what the Biden Administration would consider a “reliable assurance” from Israel by looking at the reaction of this very Administration on the merelly bringing a case against Irael to International Court for Genocide - even merely an independent authority (which, by the way, has no punishment powers) looking into what Israel has been doing is considered a bad thing by Biden.
There is a rule about Rules, which is that they’re only as good as the quality of their verification and the punishment for breaking them, so this “if they give us written assurances” with no independent verification and no clearly defined actions in case of those assurances being lies, has the strong stink of prime grade bullshit, the very same thick, intense and so strong it’s almost physical aroma that constantly surrounds this Administration when it comes to the Israeli Genocide.