As we have seen in this show and other shows magic has a price. What is the price for Juliette being a hexenbiest. Instead of it being a help for Nick some how it will be a problem. From in the woods we see she has control, it does not change her personallity. Other then looking like death what is going to be the price. A price that will surly put Nick and Juliettes relationship in jeporday.
After thinking about this the conflict will be between Juliette and the council. We know in episode 12 the council sends a bountry hunter. We know the council is charged with keeping wesen a secret, so having a human becoming a wesen would be a really big thing. Looking at it logically the last thing the wesen community would want is humans turning wesen especially turning into hexenbiest. In episode 11 the news that the council will have problems with Juliette could have Juliette having nightmares about Nick killing her. Now you have Nick faced with does he go against the council. Even more Juliette being a hexenbiest might cause even bigger conflicts in the wesen community. Unlike the wesenrein who was following old wesen law it was an antiquated law. Humans becoming wesen is a real threat to the community, suppose someone like Victor became a Zauberbiest. The plot twist is how does Nick solve this social problem. Conversation can not resolve the problem and you can not use violence.
Juliette wil not keep it from Nick very long. So far we have not seen a time when she should have told Nick but didn't. In fact we have seen several time Juliette trying to tell Nick. Telling Renard you have to remember at first Juliette just wanted it to go away. But after being a hexenbiest saved her life, she would have a new perspective. Now she wants to know more about the down sides.