What does it mean that the girl suddenly changed her personality signature to true or false?
True and false, literally easy to understand, that is to say, true and false are difficult to distinguish. As for what she means, it needs to be analyzed objectively and realistically. It is possible that she is saying that someone is hypocritical and deceptive, and she doesn't know which is true and which is false. It is also possible that he refers to a group of people who make people get full marks for everything they do.