Hillary Clinton is privately signaling to wealthy Jewish donors that — no matter the result of the Iranian nuclear negotiations — she will be a better friend to Israel than President Barack Obama. But, even as donors increasingly push Clinton on the subject in private, they have emerged with sometimes widely varying interpretations about whether she would support a prospective deal, according to interviews with more than 10 influential donors and fundraising operatives. Clinton’s private responses in some ways resemble a foreign policy Rorschach test; donors who see a deal as important to world peace have come away thinking that...