RBD - I talk with my DD about how we only see the "outside" of others, and we can only imagine what might be going on below the surface. Individuals show their "best" selves. Unfortunately DD will have none of that and refuses to believe that the popular girls are anything less than "perfect".
Fair enough, I'm sure it's easier said than done to convince them of this. It may also depend on the DD if it will resonate with her. Is she at least willing to look beyond the popular girls to try to make other friends?
I feel for you, it isn't easy to see our DC suffer.
