In most cases, 'Speak Now' isn't based on real events. It's probably the imagination of the author or creator, designed to entertain and engage the audience.
One way is to check the source. If it comes from a reliable person like an eyewitness or an expert in the relevant field. For example, if it's a historical event, a historian's account would be more trustworthy. Another way is to cross - reference. Look for other sources that tell a similar story. If multiple reliable sources say the same thing, it's likely to be based on facts.
It could mean not spreading harmful or untrue things when it's related to a real story. Maybe it's about respecting the facts of a true event and not adding false or malicious remarks.
Speak isn't based on a true story. It's a product of the author's imagination, designed to engage and evoke emotions through fictional characters and plotlines.