CHA is baiscly the sum of your appearance, mannerism, social skills, etc. Its the whole package. And Shadowheart is about as charming and sociable as a flaming barn. Maybe her looks could give here a few more points or something but overall she isent a very social character.
CHA is personality, it has nothing necessarily to do with being attractive physically or being sociable (although you could define your own character in those terms). Appearance is not a factor of the game, and social skills are dealt with using... social skills. You improve Diplomacy, Deception, Intimidation and so on if you want to be that sort of character.
A high CHA character could be ugly as sin and barely coherent in speech, so long as he or she is impressive enough to hold people's attention and sway them to his or her will. That could be by sweet-talking, but it could just as easily be by casting them withering looks. It might be charm or it might be a commanding presence. Genghis Khan was a commanding leader, and just the type to be allocated a high CHA, but he was never going to be a pin-up or a talk-show host.
Conflating CHA with being attractive is a mistake that has been made since the game began, with plenty of writers and GMs using it as a shorthand for beauty (hence you used to see blond bimbo NPCs with high CHA even though they had the personality of a goldfish).
