You are sooooooooo beautiful.
You are so beautiful that if you were to walk down the street flashing your long legs and cute belly button for all the world to see, you'd make all the boys go crazy. But that's not so good for them, because that picture of you would haunt their dreams and make their hearts break that they can't keep you.
You are so beautiful, you don't need to wear a bikini just to see if boys really will go crazy. Only insecurity depends on that sort of flattery. And you don't need to follow the trends of girls who don't care what they're doing to boys.
You are so beautiful, and if you could just be confident enough in that truth to dress modestly and with a smile, the rest of the world would see it too. When you dress modestly you are telling all the boys "My body is soo good looking that I know you won't be able to cope if I just show it off to you and then walk away. So I'm not going to put any guy through that until I find the one guy who can keep me forever." That way, guys who only want to dream of beautiful women will leave you alone, and the ones who understand why you are saving yourself will appreciate you all the more.
So when you pick your next outfit or what you will wear to the beach, remember...
You are so beautiful. Start acting like it.