Love this explanation of שום דבר - garlic talk חחחחח :-P
David F. James, B.E. from University of Montserrat (2010) Answered Jan 11, 2019 Shum is the Hebrew word for garlic. In the phrase ‘shum davar’ it literally means ‘garlic talk’, or to put it into understandable English, speech that is trivial, unimportant, and a waste of time.
This is akward in English. Normally we'd say: she doesn't want anything ... or she wants for nothing. I even searched "wants nothing except" and it wasn't pretty. It was grammar from 19th century texts and foreign language translations. There were few links... Because it's not modern English.
Some people call it double negative, but I think it's not exactly that. In modern Hebrew שום does not have a clear meaning in itself; it's pretty much like English "any", but only in negative sentences. So you can't omit the לא, but you can omit the שום (and sound more formal).