The Mirrorball Man wrote:
Has it been established that what River whispered in the Doctor's ear was his name?
This is what Tennant's Doctor said to River in Forest of the Dead, "River you know my name. You whispered my name in my ear. There's only one way I would ever tell anyone my name. There's only one time I could."
So yeah, its pretty much established unless someone can prove that 10 is lying.