Don't wear underwear and let them find out. Kinky is bad, Blindfolds are good. I love you. Go for a long walk down the beach at midnight. Write poetry for each other.
Hugs are the universal medicine.
Tell her that she's the only girl you ever want. Spend every second possible together. Tell her that she doesn't have to do anything she doesn't want to. And mean it. Look into each other's eyes.