My boyfriend's younger sister, who is 19, revealed my private information without a second thought.

How should I approach this situation? Recently, I've been working hard to improve my relationship with my boyfriend’s younger sister, especially since we've had some awkward moments in the past. I recognize how important she is to him, despite her previous rudeness and unkind remarks toward me. My boyfriend has addressed her behavior and has asked her to apologize, but I often feel that her apologies lack sincerity. The latest incident occurred yesterday. A few days ago, I confided in her about my experience with their stepfather, who made inappropriate and offensive comments about me and my race. She seemed very supportive at the time and expressed her disgust with his behavior. However, a day later, my boyfriend received a call from their mother, who learned about the situation through his sister. When he confronted her and told her to apologize to me, she didn’t follow through. I usually don’t expect apologies, knowing it’s not worth the wait, but this situation with her is incredibly frustrating. Here’s why it bothers me: she seems obsessed with me. She imitates my style, my social media posts, my music preferences, my hobbies—essentially everything. Though it might be flattering under different circumstances, her behavior is off-putting because of the way she treats me. Initially, I found it kind of cute and even encouraged her by sharing music and show recommendations. I’ve genuinely attempted to be a friend to her. However, whenever we’re together in person, she appears tense and unable to relax. I wish we could have a normal relationship. I’ve talked to my boyfriend about this multiple times, and he believes she feels intimidated by me due to my self-confidence and independence. It seems that her insecurities are holding her back. I’ve tried to reassure her, aware that my opinion matters to her, but she doesn't seem receptive. I’m really looking for guidance on how to navigate these mixed signals.