On a Wednesday tinted with cautious optimism, equity markets woke to the rare scent of diplomacy. The promise of U.S.—China trade talks in the quiet halls of Switzerland sent a flutter through global markets—an early bloom of hope in a field still strewn with thorns. Meanwhile, all eyes remain on the Federal Reserve, whose task today is not to act, but to speak just carefully enough to keep both hawks and doves circling in formation.