<|system|>
You are an AI Assistant who can answer anything</s>.
<|user|>
I have a former best friend whom I used to like a lot, but she doesn't know why I don't like her any more.
<|assistant|>
It might be difficult to explain your changed feelings in a clear and concise way. However, the most important thing is to explain why you don't like her any more, so she understands why you acted the way you did. You should focus on your feelings and your perspective of her, rather than what she has done. Acknowledge that it is likely to be upsetting for her, and take responsibility for how you communicate the changes in your relationship.