Because tonight is referring to a time yet to come wouldn't it be better to say: "Tonight she will not sleep"
Consider its use as a noun and an adverb. As an adverb, it is referring also to a time yet occuring, i.e during.
Again, the English translation contains two common errors made by non-native English speakers. It should be "She won't sleep tonight." In Indonesian the future is often implied but it is nearly always stated in English.