"I've no more business to marry Edgar Linton than I have to be in heaven," reflects the narrator's strong feelings of unworthiness and internal conflict about her marriage. She feels that her love for Heathcliff is genuine and deep, but societal expectations and personal shame prevent her from acting on these feelings.
She describes her love for Heathcliff as rooted in a shared essence, feeling more connected to him than to anyone else, including Linton. She emphasizes that her love isn't based on superficial qualities like appearance but on a profound spiritual bond that defines her true self.