The famous rift between the Dukes of Cambridge and Sussex arose from a misunderstood comment where William "genuinely" expressed concern for his younger brother, the author of a new biography has said.
Amid claims Meghan was not welcomed to palace life with open arms, Omid Scobie - who has co-authored Finding Freedom - said the Duke of Cambridge had "genuinely wanted to make sure that his brother was making the right decision", as he asked Prince Harry whether Meghan Markle was "The One".
The comment, understood to refer to the short length of time the couple had been dating across continents before getting engaged, is known to have upset Prince Harry, who took it as criticism of both his girlfriend and his judgment, the Telegraph reported.
In an interview with the Times as part of the serialisation of Finding Freedom, Scobie said: "It seems that William genuinely wanted to make sure that his brother was making the right decision.
"That said, I'm not sure if Meghan was welcomed with as wide arms as perhaps Cressida [Bonas] or Chelsy [Davy] would have been.
"I think that's perhaps because she was older and she came with a history and ... I think coming from being American."
Sources on Saturday said the rift stemmed from a simple cultural clash, with the question of "Are you sure about this?" just a natural reaction from a brother after a swift courtship and engagement.
After the Duke and Duchess of Sussex married and embarked on joint royal duties, the book says, difficulties grew, with the Duke growing increasingly frustrated at how "he and Meghan often took a back seat to other family members" in the line of precedence.
Sources on Saturday insisted palace insiders were "completely relaxed" about the contents of the book, believing it had not yet revealed any new "bombshell" that could hurt the Queen or her family.
While it promised to dispel the misconceptions about the Sussexes and set the record straight, the first extract confirms previous reports about the couple's feelings and gives insight into their frustrations within the institution.
Just before leaving Britain, the book claims, Meghan said: "I gave up my entire life for this family. I was willing to do whatever it takes. But here we are. It's very sad."
Harry, meanwhile, believed some of the old courtiers "simply didn't like Meghan and would stop at nothing to make her life difficult", working with a hostile media to make their lives in the UK impossible.
The couple are said to have felt particularly slighted by images of the Queen's Christmas message, which showed her surrounded by photographs of the direct line of succession - without them.
Senior members of staff felt the popularity of the Sussexes "needed to be reined in", it is claimed, with fears they "might eclipse that of the royal family itself".
The Duke and Duchess had "difficulty in understanding why so few inside the palace were looking out for their interests", given they were "a major draw for the royal family".
A friend of the couple referred to the old guard as "the vipers", the book says, while the authors claim rival households would drop "nuggets" of information to the media to promote their own royals, leaving Harry and Meghan concerned about leaks.
The Sussexes, meanwhile, were "impatient and impulsive", according to one close to them. "They run hot, in a way. The reactions in individual moments are definitely not the same, a month, a few weeks, down the line."
The Duke of Sussex was left infuriated by online newspaper headlines, even reading the critical comments on his iPhone and taking them to heart.
"These people are just paid trolls," he said, according to the book. "Nothing but trolls ... and it's disgusting.
"It's a sick part of the society we live in today, and no one is doing anything about it. Where's the positivity? Why is everyone so miserable and angry?"
The Duke of Sussex was particularly hurt by the settlement which stripped him of his honorary military appointments, the book claims.
"It was so unnecessary," the Duchess is said to have told a "friend" afterwards.
"And it's not just taking something away from him; it's also that entire military veteran community. You can see how much he means to them, too. So why?
"The powers [of the institution] are unfortunately greater than me."
Scobie said the Duchess was a "biracial woman stepping into the House of Windsor. That was going to ruffle feathers.
"We only need look at the Duchess Difficult narrative. What is 'difficult'? Difficult is pushy, aggressive. It's all the things that we throw on black women as a society regardless of what their actual personality is."
Asked whether he thought racism played a part in how she was treated by the household, the author said: "I would say that there are certainly individuals there who may like to take a look at how they view the world."
A second extract, to be serialised in the Sunday Times promises "the truth about the wedding and Meghan's father".
The subject is already at the centre of the Duchess's privacy court case against her father, with a detailed timeline of their estrangement and even text messages between father and daughter already in the public domain.
Royal-watchers will be keeping a particularly close eye on where the revelations have come from, after the Duchess was accused by the Mail on Sunday of invading her own privacy after five of her friends gave an anonymous interview to People magazine.
The Sussexes have already distanced themselves from Finding Freedom saying they have not given interviews or contributed to the book, which is out on August 11.