I think honesty would go a long way. At least that is how I'd handle it. You can provide her with information to possibly grow from and provide yourself with the confidence of being forthcoming and honest. I know that if someone no longer wanted to be my friend, I'd appreciate at least knowing why. It's horrible to be "ghosted" by friends and lovers.....it feels truly terrible. Honesty is not always the best policy but in situations such as this I think it is. Ask yourself if you were in your friends shoes what you wish would be done to you. That is how I formulated my own answer. If you would feel better if someone just stopped talking to you rather than being honest then you will feel better if you proceed that way. If you would prefer honesty, you will be more comfortable if you are open and honest. Best of luck no matter what you decide.