If you want to make sure a girl receives a swimsuit and wears it, you can use the sign-out trick (if you get rid of the latest patch). The latest patch that was released on December 14, 2006 fixes the sign-out trick. To get rid of the patch, go to your memory in the system blade of the Dashboard, and press:
Y, X, X, Left Bumper, Right Bumper, X, X.
You should receive a message stating "This will perform maintenance on your Xbox 360 storage devices. Do you want to continue?" If you click yes, your Xbox 360 will clear it's hard drive cache. If you click no, you'll be returned back to your dashboard menu. This will help your Xbox 360 run a tad faster and fix freezing issues. Note: this will delete all non-Arcade game downloaded content and updates, although your save games will remain. To do the gift-giving sign-out trick, give a love gift to the girl on the first day and play against her in Volleyball at least once. Then, stay in the same hotel that she is in. That night, give her a love gift. Then during each set, put on the suit you want to give her, then select the suit to give to her. During the "Now Loading" screen, press the Gamertag button and get ready to sign-out. If she accepts, she will spin into the suit. If not, sign-out and try again with the next suit you have in stock.