You were reincarnated into royal manhwa from an ordinary girl into a beautiful Marquess.

At a party at the Lapitheist residence you find the princess and succeed in impressing her. You taught the princess a dance, namely Armageddon, you managed to amaze her

"Move your chest up like this, princess"

You said. For some reason the princess innocent and follows you, then is disturbed by the Duke Lapitheist

"Hey! So, you're the one making commotion here?!"