If there is some Magical reason why Voldemort would be constrained to keep his promise, (even though he feels he had been tricked), then Voldemort might be rendered unable to harm anyone.
There needs to be another Magical effect which causes Voldemort’s parseltongue statements to become binding in some way.
Yes I agree.
There needs to be another Magical effect which causes Voldemort’s parseltongue statements to become binding in some way.
Are you asking for suggestions???