Pig Latin GUI

Question

Pig Latin is a nonsense language. To create a word in pig
Latin, you remove the fi rst letter and then add the fi rst letter
and "ay" at the end of the word. For example, "dog" becomes
"ogday" and "cat" becomes "atcay". Write a program that
allows the user to enter a word. Output the pig Latin version


That is what I have done so far

            string inputWord;
            string ay;
            inputWord = Convert.ToString(inPutTextBox.Text);
            inputWord.Substring(0, inputWord.Length - 1);
            label2 = " the word is in Pig laten is " + inputWord + ay;


But i get this error   Cannot implicitly convert type 'string' to 'System.Windows.Forms.Label' 

Could someone give me a hint or explanation please?
This is not an assignment I am just going over stuff that I learned last semester but apparently I forgot most of it.