In a word – Yes! A Pilates class is designed to give an all body workout, with particular focus on your core, helping you engage your inner abdominal muscles better and giving you a flatter-looking stomach. Since we work the whole body, the class will also do some work on your gluteal muscles, to help build muscle to give you a more shapely behind. Some exercises that will help with this are: swimming, sidekick series, and leg pull front. Read more on verywellfit.
A further note on toning also: ‘Toning’ is a combination of lowering body fat and building muscle in a particular area. It’s a bit of a myth because it’s difficult to target fat reduction in most areas of the body. What people see as the benefits of bum ‘toning’ exercises like squats is actually building muscle in that area, combined with overall fat reduction in the body. Since you don’t want to lose weight, you should focus on exercises that build muscle in your focus areas. Read more on fitnessrepublic.