Complex sentence: Some have stated the relationship between she and Diana was strained, because of her long resentment of Charles marrying Diana and not her, though others including Diana's biographer Andrew Morton have said she was one of the only people Diana trusted.
Split into simpler sentences: Some have stated the relationship between her and Diana was strained, because of her long resentment of Charles marrying Diana and not her. Though others including Diana's biographer Andrew Morton have said she was one of the only people Diana trusted.