Fiction? Read a little 20th century history outside from countries outside of the US or talk to people there (Latin America would be a good example) and you'll find out it's anything but fiction in the general practices (if not in the specifics).
The US policy he talks about is real enough, but autobiographical points struck me as questionable.
It's pretty well known that intelligence services and others placed female agents in positions to develop sexual relationships with men and women in order to get information and apply influence. Hell, US propaganda books and movies (The Green Berets) have featured women in this role as quasi-heroines.
I'm not asserting that the book is credible or not, I recall reading it a long time ago and honestly don't remember enough about it. But if the person is what he claimed to be, seems like the type of shenanigans that would take place.
"One former CIA officer said that while sexual entrapment wasn't generally a good tool to recruit a foreign official, it was sometimes employed successfully to solve short-term problems."
https://en.wikipedia.org/wiki/Clandestine_HUMINT_asset_recru...