Why did the rabbit untie the red line? Didn't the brother and sister make up?

-(Long time no see) Actually, my brother meant well. Especially in the end, I encouraged my sister to say: even you can. My sister's understanding is that my brother still feels like a turtle and still looks down on her. So the promise of childhood (being a bride) can't be realized. So I exiled my brother because of love and hate. In fact, this sister's idea is also very simple.