‘Lines’ are what an actor must read, learn remember and say in their acting roles. Actors of course do not mean what they say when they speak these lines. It’s acting. I’d need more context, but it seems that ‘line’ here is meant as something practiced, rehearsed and not genuine in its delivery - a practiced lie.

Or it could be a typo!!!

@Chris thank you~

Yes. In this context, line means lie. New Oxford American Dictionary line - informal a false or exaggerated account or story: he feeds me a line about this operation.