Samantha accused Markle of "fake waves and smiles" in her most recent public tirade after it was revealed Meghan hadn't spoken to their father in months.
The 37-year-old Duchess of Cambridge, who is set to visit Australia with her husband, Prince Harry, next month, has apparently "lost touch" with people from her former life after embarking on her new royal role.
Taking to Twitter, Ms Markle wrote: "I am not candy coating anything anymore!"
In particular, since she's been betrayed so consistently by her father Thomas Sr, half brother Thomas Jr and half sister Samantha Grant, she feels she can only trust her mother Doria Ragland, who is spending an increasing amount of time in London to support her daughter. "The duchASS can bow to the daddy".
She added, "She owes my father a lot of love and respect. It's her private life", said the source, adding: "The beginning of marriages are not that easy, but to have that impetus of your own family being disloyal is disgusting and embarrassing".
"That might be just having a couple of bad days".
"All I can say now is that I think Meghan was calculated - very calculated - in the way she handled people and relationships", Ninaki said in an interview with the Daily Mail. But since announcing her engagement to the British royal a year ago and their wedding in May, she has moved full-time to the United Kingdom where she is trying to forge genuine connections of her own. "It really was most thoughtful of you and Her Royal Highness sends you her heartfelt thanks and best wishes". I think she's under too much pressure.
"There's a high price to pay to be married to that family".
It's a popular opinion that fans of the royal family absolutely adore Meghan Markle, but what about the royals themselves?
Those who wrote letters to Meghan received a postcard with a picture of her interacting with a crowd and a short but sweet message at the back.
Kensington Palace has not yet commented.