How do I reduce thigh fat quickly without stress?

While spot reduction of fat is not possible, training a particular muscle to make it strong and toned can be done easily. You can target your thighs by doing some curtsy lunges, goblet squats, and sumo squats. Do some lateral lunges and side leg raise to focus on your inner thighs.

There really isn't a way to reduce fat quickly or to sport reduce.  Liposuction is about the only way to actually target where fat will be removed, but even this procedure takes a couple of months to show final results and only a small amount of fat can be removed.

Assuming that isn'[t really an option for you, the answer is change your diet and exercise program.  If you are in a calorie deficit and eating mostly protein, vegetables and good fats, your body will burn stored fat from where you are storing it.  Over time, you'll slim down the area that have extra fat.  Daily exercise will help tone the muscles under the fat.