# Why does two masses with energy attract each other?

I have heard that every mass attract another mass with a force directly proportional to the multiplication of their masses and inversely proportional to the square of distance between them, but newton doesn't told that why two masses attract each other. Also I am familiar about the curvature concept considered by Albert Einstein according to which gravity is not a force but a curvature caused by imbalance in spacetime by mass/energy. Bit if there is a curvature how can you prove it?