Grand Vampires are quite a bit more difficult to slay now. The chance mostly depends on how Nice the vampire is, but the chance is also increased a bit if the vampire you are trying to slay is a Grand Vampire. If you lose the Slay interaction, there is a small chance the vampire will bite you and turn you into a vampire. Sims can now autonomously perform the Slay interaction. I highly recommend you get UPDATE 1, because it adds a lot to the mod.
UPDATE 1: This update changes the mod quite a bit, so I will be leaving the original version up for download as well. You should only download this version if you have Romantic Standards UPDATE 75 or later. I am releasing a Romantic Standards Version of this mod which makes the two mods compatible.
Romantic Standards Version: UPDATE 75 of Romantic Standards made the two mods incompatible.