Like many other mentioned, welcome to human psyche, where your PoV does not have to match the PoV of others. Some need awareness that external validation exists. Some need awareness that while it exists, it does not have to be more important than your own view. There is no cookie-cutter option, sadly.
Best case scenario is - teach a kid that their view is valid and true, while also pointing out that people have so varied tastes that she will always be considered attractive and we have no "hard" definition of beaty - it's all subjective, both within and without.