A puzzle about truth and singular propositions

It seems that every singular proposition implies that the object it is singular with respect to exists. It also seems that some propositions are true with respect to possible worlds in which they do not exist. The puzzle is that it can be argued that there is contradiction between these two principles. In this paper, I explain the puzzle and consider some of the ways one might attempt to resolve it. The puzzle is important because it has implications concerning the way we think about the relationship between a proposition and the claim that the proposition is true.