Go to the Summary tab of your iTunes sync settings and confirm that you have checked "Sync only checked songs and videos". Then tap the Tones folder on the top left side of iTunes under Library (see image below). (If you don't see the Tones folder go to iTunes Preferences and on the General tab below Show check Tones.) Now to the right check the ringtones you want to sync to your phone). Then click on the name of your phone on the left side of iTunes and go to the Tones tab and check Sync Tones. Now sync your phone. If you still are having trouble syncing ringtones to your phone see https://discussions.apple.com/docs/DOC-3792.