The problem is - there's no such thing as toning. You can make muscles bigger and stronger (not MASSIVE - you would need a very specialist diet with supplements to build significant muscle as a woman), and, crucially, you can remove/thin out the layer of fat covering your muscles.
You could have muscles like Arnie, but covered with fat you would still be un-toned.
It's not possible to lose fat from a specific body area. All you can do is lose fat all over (an area where fat is thickest loses more, obvs, but proportionately it will be the same as other areas e.g. Hands, face, lower legs).
To reduce size of bum and hips and build lean muscle tissue, do fat-burning intervals and bodyweight resistance exercises.