King Charles Had a Brutal Six-Word Response to Princess Diana Before Divorce: "Why Can't You..."

To this day, Princess Diana's tumultuous marriage with Prince Charles is a topic of public intrigue. Though a lot of information is already known, more intimate details keep emerging from sources close to the former royal couple. Like Charles once said to Diana six words that hurt her so deeply she never recovered from, eventually parting ways with Charles.

Though she shared a few things in common with the royals, such as their love for animals, skiing, horseriding, and, of course, philanthropy, she struggled to follow the royal rulebook. Unlike her fourth cousin and sister-in-law, Sarah Ferguson, who married Charles' brother Prince Andrew. 

Ferguson quickly blended into the family. Royal expert Jennie Bond revealed Channel 5's Fergie Vs Diana: Royal Wives at War, "Fergie fitted in really well [and] threw herself into the family life. She was the good fun, a frolicking girl who was the breath of fresh air" in the royal family. Diana, on the other hand, was perceived as the "moody" one by the people, per The Mirror. 

Disappointed, Charles compared his "vulnerable" wife Diana to Ferguson and asked, "Why can't you be more Fergie?" These six words reportedly cut through her already low self-esteem. Psychologist Jo Hemmings weighed in, "That wasn't just a rebuke. That would have been one of the most cutting, hurtful remarks that her husband could have made to her." 

Charles' cut-throat remark added to their already tortured marriage. Following their split, Diana shared multiple personal details of how her marriage to the now-king collapsed. For instance, in the book Diana: Her True Story in Her Own Words, the late princess recalled, "In my immaturity, which was enormous, I thought that he was very much in love with me," adding that his "besotted look wasn't the genuine sort." 

While Diana's marriage ended in divorce, so was Ferguson's. Before becoming sisters-in-law, they were fourth cousins and close friends. Although it was one of the most cherished bonds Diana had in the royal family, it eventually turned sour. The Duchess of York recalled in her 2011 book Finding Sarah, "Sadly, at the end [of the princess' life], we hadn't spoken for a year, although I never knew the reason, except that once Diana got something in her head it stuck there for a while," per Us Weekly.

Being cousins, they had known each other since adolescence but reconnected as friends in 1980. Ferguson, who was 21 back then, was in attendance when Diana, 19 at the time, tied the knot with Charles. The twosome hit it off with their shared sense of humor as Duchess told Harpers Bazaar in 2007, "Diana was one of the quickest wits I knew. Nobody made me laugh like she did." 

In her lifetime, Diana never really spoke about her equation with Ferguson, but the latter expressed her grief of losing her, saying, "I really miss Diana. I loved her so much." But, unfortunately, the sisters never got time to sort out their differences as Diana died too soon, in August 1997 at the age of 36.