Your objective in Date Ariane, is basically to have a pleasant evening. That said, the game offers tons of possibilities, so it all depends on what you consider to be 'pleasant.' Some dates may end with a game of Parcheesi, others with a slap to the face, and others with a goodnight kiss. Who knows.
As usual in this type of game, the gameplay in Date Ariane is very simple. Basically, you have to make decisions, choose what to do in each moment and how you want to respond to Ariane's questions and suggestions. The ending of the game all depends on your behavior.
Date Ariane is a really interesting visual novel that offers tons of different situations. Since it's about a blind date, some of the scenes in the game can end up being a little 'racy,' but it's also possible (and probable) that the date with Ariane simply ends up being a nice dinner and nothing more.