For any working to be successful, there actually has to be a chance of it working.
Unless you are personal friends with Emma Watson and she knows you well too, love workings are not going to be successful. It is much better to undertake love workings generally, to attract potential partners to you, rather than trying to attract any one particular person.
Also Vodou is a religion, not a kind of magic. There aren't Vodou spells. They sometimes use a sort of magic called hoodoo, and some consider ritual work to be inherently magic, but they aren't mutually binding. Not every Vodouist uses hoodoo, not every hoodoo practitioner is a Vodouist.