A well-known royal watcher, with inside knowledge, has opined that:

Diana was a spoilt brat.
She was so immature -
she had an emotional age of 14.

With that revelation in mind, this doesn't seem so hard to believe:

Back in the mid-1990s, long before he was President, criminal defendant Trump apparently had quite a thing for Diana—which led to a series of bizarre and complicated news items that made headlines all over the world.

At a dinner, Trump reportedly offered Diana a free membership to his Florida golf club, Mar-a-Lago, which she declined.

But Trump was smitten, according to British television journalist and longtime Trump antagonist Selina Scott, who hosted a 60-minute documentary about Trump for the U.K. network ITV in 1995. In a 2015 article for Britain's Sunday Times, Scott said(opens in new tab)that shortly after Diana's 1996 divorce from Prince Charles, Trump sent massive bouquets of flowers to her at Kensington Palace. Scott, who says she was a friend of Diana's, reported the princess saying that Trump gave her "the creeps."

Scott went on: "As the roses and orchids piled up at her apartment she became increasingly concerned about what she should do. It had begun to feel as if Trump was stalking her."