TV
There’s something that happens when you discover the truth about someone. I know a little about this. The truth changes everything.
— Sydney • Alias

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker claims that discovering the truth about someone changes everything, then invokes personal familiarity with that experience. The broad language conveys the force of a revelation without identifying it. What mattered before may look different once that new knowledge reshapes the observer's understanding.
Context reviewed