Trying to cut down sugar/sweets in my diet. Are there any alternative sweeteners that are safe and don't cause unpleasant side effects?

Erythritol, stevia. I agree with Dr. Jayaraj that stevia is a healthy alternative sweetener but not everyone likes its flavor. Erythritol may be the safest natural sweetener available and tastes more like sugar. See Xylitol is another good choice, though large amounts may cause loose stools.
Safe substitutes. Stevia is the best non calorie plant base sugar substitute.Do not use other chemicals. may use honey in between. High protein diet,handful of nuts daily- Salad & salmon diet. Keep off of fructose & fructose products.