And she longed with an intensity that outbalanced for the time every other feeling that he should confess his sin fully, entirely--see it in all its ugliness, and gather himself together into a deep repentance before he went down into silence, or before he made a fresh start in life.

She would have given her right hand to achieve that.
And in a lesser degree she was drawn towards Lady Newhaven.

Lady Newhaven was conscious of the tender compassion which Rachel felt for her, and used it to the uttermost; but unfortunately she mistook it for admiration of her character, mixed with sympathetic sorrow for her broken heart.

If she had seen herself as Rachel saw her, she would have conceived, not for herself, but for Rachel, some of the aversion which was gradually distilling, bitter drop by drop, into her mind for her husband.

She would not have killed him.