In Chrono Cross we know that characters have purposefully lied to conceal what's really happening in the story. Belthasar is the worst offender, but anything FATE, the Dragon Gods, or anyone else states could be entirely fictional.
Presumably, every event observed in Chrono Cross was essentially fabricated, so we cannot be positive of the validity of visible evidence.
In an RPG, there is no omniscient narrator, and we do not experience any character's first person perspective. How much of Chrono Cross, or the entire series, can we take at face value?
What do you think we should do?
Accept all information given unless it is proved false.
Judge the reliability of information based on the number and trustworthiness of the sources.
Be highly skeptical of all sources.