I don't absolutely believe OP's story, but an important feature of OP's story is not naming any names.
The story contains various propositions that can basically be divided into:
1. propositions that can likely be independently corroborated by large numbers of people:
--- the conference really happened (we are not told which conference where, but if we knew that, numerous people could be found to attest to it, if it had been real).
--- that the organizer was loudly accosted by the woman, accusing him of stalking: this is a public incident that supposedly happened, in front of witnesses.
--- the non grata couple is real; people don't like them for some reason and warn conference organizers
--- the non grata couple are known for harassing behavior
2. claims made by the organizer, like:
--- he denied participation in the conference to the couple
--- he was harassed by the woman with repeated contact attempts
--- the woman's allegations were false
The claims under (1) are verifiable true or false. If they are true, they lend overwhelming credibility to (2). Basically if everything under (1) is true, it's almost inconceivable that the (2) claims aren't.
The story contains various propositions that can basically be divided into:
1. propositions that can likely be independently corroborated by large numbers of people:
--- the conference really happened (we are not told which conference where, but if we knew that, numerous people could be found to attest to it, if it had been real).
--- that the organizer was loudly accosted by the woman, accusing him of stalking: this is a public incident that supposedly happened, in front of witnesses.
--- the non grata couple is real; people don't like them for some reason and warn conference organizers
--- the non grata couple are known for harassing behavior
2. claims made by the organizer, like:
--- he denied participation in the conference to the couple
--- he was harassed by the woman with repeated contact attempts
--- the woman's allegations were false
The claims under (1) are verifiable true or false. If they are true, they lend overwhelming credibility to (2). Basically if everything under (1) is true, it's almost inconceivable that the (2) claims aren't.