I understand, and I disagree with your statement. The rest of Canada can hold its own referendum on the issue, but it would basically be nothing more than a large-scale public opinion poll. International law recognizes the right of peoples to self-determination, and in fact the House of Commons has already recognized Quebec as a nation. After winning a referendum, the National Assembly would likely unilaterally declare independence, and at that point it becomes a question of international recognition.
Hopefully it would be after a significant winning margin, say over 55%, ideally 60%. I am not a partisan of holding referenda until one passes at 50+1, because although democratic, it isn't a politically stable option. However I do belive we will achieve 60%+, in time. And after indepedence, hopefully we can negotiate close economic integration with our Canadian friends.