Sarah was laughing because she was surprised and happy. This can be made explicit. Alternate translation: "God has caused me to laugh joyfully" (See: [[rc://en/ta/man/jit/figs-explicit]])
What people would hear can be stated explicitly. Alternate translation: "everyone who hears about what God has done for me" (See: [[rc://en/ta/man/jit/figs-explicit]])