<human>: Condense the text into a few key points

My friend is already a fairly introverted person and she is more sensitive to anxiety than most. She doesn't let people close to her easily and rarely opens up to people outside of her close family circle. However, I am someone that she confides in with things that she doesn't tell anyone else. However, I am not so great at showing emotion. It is something I am working on, but I don't want to appear aloof or coldly stoic when she opens up to me about her insecurities and issues. I want to validate her feelings, her thoughts, and her sense of self. What can I do to make her feel warm and safe?
<bot>: Friend confides in me about her self-esteem issues as a result of her cheating boyfriend. I'm not sure I'm showing enough emotional warmth.