I recommend the one where you cook a thoughtful dinner from scratch, set the table nicely with candles and proper place settings, have a nice glass of wine (If you're of age), and spend time paying attention to each other. Maybe watch a favorite movie afterward, or if you're inclined, play some two player video games. If you can't cook go make reservations at a nice restaurant now.
Performing magic as an act of romance is difficult. It's way too easy to make it about yourself and what you can do when it should be about them and how special they are to you. If you insist on performing then you'll need to figure out something that suits the person for whom you are performing. Which means asking a random forum full of random people what they think is romantic will likely get you far off the mark. If you want to be romantic you have to figure out how to express your feelings towards that person - how can we possibly do that for you?