If I start eating healthy and wearing a waist trimmer that makes you sweat more while exercising will I lose water weight and fat or water weight only?

Most waist trimmer. belts are made of a rubber substance (Neoprene) and promote sweating where applied.Yes, there is more sweating/loss of water, but the amount is small and does not contribute significantly to weight loss. Your healthy eating plan, especially if you have a modest calorie deficit each day, is much more likely to result in weight loss including fat, water, and hopefully not too much protein. Stay well.