Of Greek or Welsh origin.
It is rather the feminine form of the name “Yvain“, associated with “Eugene” or a combination of the names “Yvonne” and “Elaine”.
Sources mention Yvaine’s meaning as “evening star”, due to Neil Gaiman’s novel “Stardust”. In the novel, also adapted for the movies, Yvaine is the “fallen star” feminine lead character.
When deriving from the name “Yvain“, Yvaine means “well born”, “polite”.
Other forms of the name are: Owena, Eugenia, Evgenia.
In the following short video you may watch the trailer of the film “Stardust” and get an idea of the name’s romantic charm: