Much of our physical appearance is beyond our control
True, an ugly woman will not become pretty not matter how much she tries. However, there are many things a woman can do, to go from merely plain or unattractive, to positively repugnant.
Few come to mind: poor hygiene, gaining weight, getting tattoos, chopping her hair off, dying it in an unnatural color, dressing masculine, having a sour and entitled attitude.
So all women, even those who are not born naturally beautiful, can strive to at least have good hygiene habits, stay slender, groom their hair, dress femininely, smile and open their mouths to only say nice things.
Everyone knows deep down inside that there are objective standards of beauty. Nothing wrong with that.