Cannot implicitly convert type `void' to `bool'

I am having trouble with this script. As of now Unity is telling me that I "Cannot implicitly convert type “void” to "bool. I am trying to end my game with the broadcast of “Game Over”. I am using the update to wait for the broadcast and then use update to end my game. Any help would be great and suggestions would also be awesome. I am new to Unity and any help would be appreciated.

void OnTriggerEnter(Collider other) 
{
	if (other.gameObject.CompareTag ("OOB")) 
	{
		other.gameObject.SetActive(false);
		SendMessage("Game Over");
		Debug.Log ("Game Over");
	}

}

void Update()
{
	if (SendMessage ("Game Over"))
	{
		Debug.Log("Game Over");
	}
}

`

If statements check whether the argument you passed is true or false, which means that the argument you pass in has to return a boolean. Send message returns nothing, so its return type is ‘void’. I’m not sure if you actually understand what the method SendMessage does, but I’ll give you a quick rundown.

SendMessage looks through all MonoBehahaviours on that game object to see if it can find any function by the name of “GameOver”. So this means that if you wanted to have a game over sequence, then you could put your code inside of a method called “GameOver”.

Here’s a link to the Unity Scripting API. If you haven’t looked through the tutorials, manual, or api yet, you should definitely do that.