Does she not or doesn't she?

I'm curious, could you clarify the difference between "Does she not?" and "Doesn't she?" in the context of forming a question? I'm trying to understand if there's a subtle distinction in meaning or tone when these phrases are used, or if they are essentially interchangeable. Is there a particular scenario where one would be more appropriate than the other? I'm particularly interested in how these phrases might be perceived in formal and informal settings, as well as in written and spoken communication.