Now Israel wants a written guarantee that, evidently was what was agreed upon by Netanyahu & Hillary Clinton about the 20 stealth air crafts to be given as a gift. But there seems to be second thoughts This comes because of past disappointments. But philosophically .speaking an oral,verbal promise is stronger. Here we get into the realm of trust & honesty, Any self respecting nation nation cannot break that promise,especially, a great world power where other nations are also watching to see her behaviour.
4 UN peacekeepers injured in Sinai and taken to hospital in south Israel (Haaretz)
from the article: U.S. ready to offer Israel written guarantees if it restarts peace talks