That right there is the whole theme of the series. The narrator stated it right from the very beginning, the entire entertainment world is built on lies, fully self-aware, and only the audience is left out of the loop when they willingly choose to do so and believe all the lies they're shoveled.
Ai in particular gets a full character arc on how her life was built on lies. She's honestly a bit of a sociopath throughout the arc, but she also knows it. She's never been loved and has no idea how to genuinely show it, but was more than happy to feed the Lie of Love to her audience in the hope that the lie would eventually be made real. Her initial motivation to have children was a mistake, because she was hoping to be forced into the position of loving them and finally learning what it meant. She was deathly afraid of it being a lie, which means she'd be as irredeemable as her own mother. Thankfully, her worries were just in her head, and she got what she wanted all along, if bittersweet.
Aqua and Ruby have the same thematic core problems. Ruby was abandoned, though not as completely as Ai was. She's also not sure if it is okay to actually strive for what she wants, and we saw that in the dance practice scenes. Aqua is so damn good at lying, that he is starting to lose a sense of what's actually true. His genuine love for Ai has twisted into a weird self-destructive desire for revenge, and he's also been lying to Ruby to keep her "innocent," like Sarina was to him. He just doesn't know that she isn't either, because he couldn't make the connection that she really is Sarina, and he didn't know her quite as completely as he thought.
The scene with child-actress Arima Kana was a different perspective on lies, one for good. The Director lied to Kana and used Aqua to do it, in order to break Kana of a budding pattern of arrogance that would only hurt her career in the long run (like many child actors who get full of themselves and then find all their roles vanish). He used non-actor Aqua to humble Kana. She broke down because her pride was shattered, but desperately asked for more takes, which will only make her better.