Is it true that Sun revolves round the Earth?

"The Sun rotates around the Earth".This statement cannot be written/stated as "FACT" because there is no physical reality.Yes,we can draw lots of inferences from the above statement.

Let me explain what is common in the classical mechanics and general relativity.

The Sun is more massive than the Earth.In terms of classical mechanics the Sun exerts a way stronger gravitational force than the Earth..
Sun is way stronger than the gravitational field of the Earth. The point is: the Sun being more massive than the Earth, is independent from choice of frame of reference.Thus if you do not have frame of reference you cannot talk about rotation/revolution.Then how can you prove that Sun revolves around the Earth.This can be one of your inference or assumption but not the fact.

For the case of the Moon and the Earth and the Sun: The common center of mass of the Earth-Moon system is orbiting the Sun. The Earth is so much more massive than the Moon that the common center of mass of the Earth-Moon system is beneath the Earth's surface.

Again,this is independent of choice of reference frame. Regardless of how you represent the physics taking place, the physical description locates the common center of mass some distance beneath the Earth's surface.

The General theory of relativity given by Einstein is derived from classical mechanics only. The first step is the realization that classical mechanics and Newton's law of gravity admit of a geometric description.The relativity always speaks about the relative motion concept which need a reference point.