I need an explanation

On the other side, Ariel flung Aaron's arms off her shoulders and stormed inside. When Aaron saw that Ariel could walk with a little limp, his lips set into a thin line. He indeed had some suspicions, but he still held hope towards Ariel. Aaron believed that Ariel would at least have a bit of shame left in her heart and wouldn't do something so shameful as interfering between Ari and Noah.

Not when their relationship was already crumbling like wet sand.

However, his elder sister showed him why exactly he shouldn't have held even the smallest flicker of faith toward her.

He glanced at the furious Ariel who was heading inside the house and then turned to look at his mother. Mrs Harlow's face was twisted in a deep scowl that had a hint of worry. Aaron couldn't help but wonder why she was worried.