It's hard to understand when you have no previous experience with ED. But it seems that you must really care for her to be reaching out to this forum and from what you wrote I can tell you that you are not alone in those feelings as many of my own family/friends were often frustrated with my ED. Not understanding is not a crime, an ED is a hard illness to understand. Just try to keep in mind though that typically an ED is not about trying to look beautiful but about control. An individual with ED usually feels that they cannot control some aspect in their life and will control the only thing they feel like they can control, what they eat (or don't eat). An ED is something that also takes complete control of someone's life. With my own ED it was all I ever thought about: not eating, exercise, calorie restriction, self punishment for eating, etc. So this may be the reason why your attempts at telling your GF that she is beautiful will fall on deaf ears. What you may find helpful is to do exactly what you are doing now: talking to people who are knowledgable about EDs (either through personal experience or a professional) to understand more about what your GF's ED. Also, allowing yourself to get some self care by joining a support group or community just for people who have loved ones with ED. Finding your own space to keep mentally healthy too is important because there will be plenty of tough times ahead. But there is always plenty of support out there for both of you. No shame in seeking help out! There are communities that can help and embrace the both of you. All the best.