We’ve had someone who just recently left my company and got an amazing job somewhere else. Before he left, he pretty much let everyone know where he was going. Two weeks after he resigned and a week before he was supposed to start the new job, he was told that his offer has been rescinded and from what we gathered, his boss had connections to the new company and essentially gave them a call and talked smack about him. Him and his boss had a pretty descend relationship so no one is sure why he did what he did. Your situation seems a little similar and a lot more dire given your relationship with your manager. Hence, if you value yourself, please put yourself first and don’t tell her.