It’s all the trauma she faced when she was younger. Because of being constantly watched and having to put on a face whenever she was with her brother, she is probably extremely skilled at hiding her emotions
Due to her trauma she doesn’t think she can take the risk of letting him know. Imagine if you were completely alone, you could only rely on yourself, and you find a person who treats you well and puts you first. You would do anything you can to NEVER get on their bad side. She believes that if she shows him who she really is, she will lose that connection forever. In reality, that is not true, but when does reality matter when you have CPTSD from being abused your entire life. Her true self was always discouraged both in her previous life and current life. Most of the times it was met with a beating by Cesar.
I understand your point but putting yourself in her shoes, it’s hard to open up to people. Especially if you never have done it before. She’s just scared he won’t like her anymore once her perfectly craft image crumbles.
idk how she just laid down quietly, if i was in her place I'd start bawling the moment my head would hit his lap