I know one of the main reasons for Adalind not wanting to tell Nick she was a Hexenbiest again was because, well, Grimm x Hexenbiest are mortal enemies BUT after re-watching Season 3 episode 18 this scene popped out at me. Nick tells her he is not there to hurt her OR take her baby. YET, he did help take her baby away from her. So when she tells him in Season 5x18 that people change their mind,I think that moment played a part in her not wanting to tell him. He did change his mind which can make her unsure. of his reaction. They were in a different place back then but those kind of things tend to come back as reminders and “what ifs”.