If only Arabella were the type of sister who just stole clothes from Clarissa's closet. Unfortunately, she can't even be in a room with Clarissa for two seconds without starting a catfight, and that takes some doing. It's sweet, innocent Clarissa, for goodness sake!
Okay, so Clarissa technically snaked Lovelace right from her big sis. And fine, Clarissa got all the looks and the smarts. But if Arabella's good at one thing, it's making Clarissa M-A-D: "Bella has not a feeling heart: the highest joy in this life she is not capable of, but then she saves herself many griefs by her impenetrableness" (42.50). If we didn't know any better, we'd say that Arabella is the only one who can crack Little Miss Perfect's sunny exterior. But if Clarissa is right, Arabella is terrified of letting her guard down. That's got to be tough.
Arabella isn't terribly sympathetic to her sister, but it's not like she wants bad stuff to happen, either. Let's just say that she's the type who can't resist saying "I told you so!" when it's, like, the last thing anyone wants to hear.