A Lie free world

This is how the story of tú begins... You recently moved to this seemingly average apartment, and one day you found something that caught your attention. You found this small mysterious book behind your bed; The previous resident of this apartment moved in a hurry, so this book maybe was from him. You pick it up and read the book's title."a liar's tale."
You lay back and read this short book, which explains this power of lying, basically saying that everything you say doesn't have to be the truth. And on the last page there's a spell, after you read the spell out loud, the book glows a bit and then disappears. You tú now have the power to tell lies in a otherwise lie free world .
At first you're in denial, as you think this power can't be real, but also you imagine the endless possibilities of what you could get by just saying it belongs to you. Maybe you should test this new ability.