I had not intended to make any videos of Princess Debut, but it really is quite endearing. There are three Princes who will be eager to become your partner almost from the very beginning of the game. Luciano is not one of them. If you wish to persuade Prince Luciano to become your partner, you must refuse to invite any one else, then participate in the first Dance Competition with a large Rabbit instead of a romantic Prince! The Rabbit, whose name is Tony, is your character's dance instructor.
Here is the series of events that involves Prince Luciano, giving an early option to make him your partner.
After making this video, an Anonymous player wrote a comment to the effect that, if you make Luciano your Partner before he leaves to participate in the World Dance Competition, he never will return and you will be left without any hope of dancing with him again.
As I am a stubborn individual and was appalled moreover by the prospect, I tried to disprove this assertion... Having played through every possible scenario, however, I still failed to elicit Luciano's return on the 29th day in my own game.
Now, another player has informed me that he/she did likewise, playing through the game FOUR times in every possible manner to see if there was any way to bring Luciano back if he had become your partner BEFORE his departure.
I therefore believe it may be necessary to caution players against any decision to make Luciano their partner BEFORE the 29th day... What this means in practical terms is not having ANY partner throughout most of the game as Luciano only returns to become your partner on the 29th day if you have remained partnerless throughout the game.
Later: The video showing the 'happily ever after' ending with Prince Luciano is included in a later post. In order to have Luciano as your Partner for the Ball, you must ask him only on the 19th Day when he goes with you to the Practice Hall for one dance. You must ask him to be your partner then, although he will refuse, knowing he plans to leave for the World Dance Competition. If you do ask him, however, he will invite you to meet him the next day.
On the 20th Day, meet Luciano and promise that you will wait for him. If you do not have a Partner and remain single throughout the period of his absence, he will return on the 29th Day to take you to the Amusement Park, where he will ask you to be his Partner.