Sorry, but such a case is almost impossible to win, at least in US.
Mrs. Trump is a “public person.” As such it is her legal burden to PROVE that the story was published WITH THE INTENT of damaging Mrs. Trump, and the newspaper KNEW it was false.
Proving such intent is virtually impossible.
It would be an easier case in the UK, but still long and difficult.
I’d argue she is not a “public person.”