There absolutely is verifiable evidence.
Patrick Jephson, Diana’s former private secretary for over seven years won substantial damages believed to be around £100,000 and an unreserved apology from the BBC following the Dyson report which investigated Martin Bashir’s deceit of Diana, involving forged bank statements, which deceived Charles Spencer in to thinking that Jephson was being paid by ”hostile entities” to spy on her. This in turn led to Diana believing that Jephson and other loyal aides were spying on her, totally destroying her trust in him and making her reassess her security arrangements.
And the Dyson enquiry established that Bashir then kept feeding Diana worrying stories, one of which ironically, that a plot existed to kill her.
And believing she had been betrayed from within, Diana withdrew from the very people who could have guided and protected her and put her trust in people who couldn’t.
Jephson was in this way alienated from her inner circle, and their professional relationship broke down and lead to his eventual resignation, when prior to that they had had a very happy and successful working relationship even though Jephson was there while Diana was navigating a very difficult divorce and negotiations over the custody arrangements for the princes.
For over 25 years, Jephson was haunted by the fact that Diana died believing he had betrayed her.
Incidentally Jephson donated the entirety of his damages to charity, especially a children's hospice in Wales that had been the focus of Diana’s first official engagement.
Anyone in any doubt about this should read
Dianarama by Andy Webb, a really excellent investigative journalist, who has dissected the whole sorry episode in detail.