It's rude not let a sibling use your things.
Jenny's sister asks to use Jenny's makeup because she wants to look nice for her date that evening.
Jenny wants to respond to her sister's request.
Jenny says it's okay for her sister to use Jenny's makeup and even helps her sister put it on.
Jenny tells her sister to get her own makeup if she wants to wear makeup.
Jenny's sister is happy Jenny is willing to share things with her.
Jenny's sister thinks Jenny is very selfish and vows not to let Jenny borrow anything from her ever again.