It depends on which path you are on (you can be independent, involved with Kira or involved with the vampires, and this can slightly change the requirements). Also, did you go talk to the owner himself back in Tarkas? Maybe you already did everything and you just need to report back, or perhaps you didn't find/check the hiding spot inside the cart.
The best sequence is "try to sound eager", "beg them", "impale yourself". If you win, you do get back to doing the chores, but there should be a new slave to interact with, and which you will be tasked to "bring up to speed".
I kind of agree with the general sentiment (as in, I'd prefer if the players talked about it among themselves, it's better for the community, and it's less unnecessary work for me), but I get so many questions even with a walkthrough, and generally if someone asks for help and nobody replies in a while, it feels weird not to say anything if I know the answer. It's like being around someone who asked "what time is it?" and having a watch. XD
There was a hint when you picked up the book, and you can see the hint again if you check the "small note" in your inventory (it should be among your key items).
During the "Under the Moonlight" quest, you can meet some wolves in the forest. Losing to them starts that path. I might add another way to become a werewolf in the future, but for now that's it.