I have been there two years ago and believe me you have nothing to worry about. I asked the same question before I left and I did some reading Sicily  has low crime rates. There are some gangsters but the mafia doesn't want to interfere with the local business. Taormina is considered a safe town. Furthermore like I would recommend to all tourists don't look too much as a tourist. Have a great time she is beautiful....

Here is some more info up to date.