To have a successful date you will need to raise the Mood to 5/5 and kiss the character.
Talk to them and give gifts they like to raise the Mood to be full in order to kiss.
However this does not happen if you skipped the scene or decided to go back to sleep during Vanni's arrival cutscene.
Cheat Codes can be earned by getting different endings.
Once you have enough successful dialogues with the character, a message letting you know that you can now go on dates with the character will appear.On the day of the wedding, go to the church to talk to the character you would like to end the game with.If you have raised your Relationship EXP with them to be high enough, they will appear at the church. The goal of a dating sim is to raise your Relationship with characters and after falling in love, to have a happy ending with them.Raising your Relationship can be done by talking to them, giving them gifts and going on dates.