Drinking hot water is not going to magically make you lose fat from neither the belly nor any other place. Water by itself will make you feel more full, leading to some people eating less, but it will not make you burn calories by itself. That being said, drinking a lot of water is good for your overall health, so you should definitely do that.
As for losing weight; increase your activity to burn extra calories, while also paying attention to not eating unhealthy. Aim to have a daily calorie deficiency.