Animandel - Taiwan has a reputation as a place heavily involved in human trafficking. However, I'm not sure that the dangers of a tourist being kidnapped is much greater than it would be in one of the European countries. A woman traveling alone should take more precautions. That may sound sexist, but I think that's a valid warning, especially in areas where women are not seen as equals to men.
This being said, I think the biggest danger in Taipei, Taiwan is the risk of being run over by a scooter. The traffic rules there are similar to other countries, but no one seems to follow them and the police aren't very interested in enforcing the rules of the road.
Don't let fear keep you from making the trip if you want to go. Plan your trip ahead of time and learn where you can go and the places you should steer clean of.