Getting error- not all code paths return a value

public string randNum()
{
    int randomNumber = Rand.Next(1, 9);
    string guessed = "";
    while(guessed !="correct")
    {
        if(randomNumber > number)
        {
            guessed = "too low";
            return guessed;
        }
        else
            if(randomNumber < number)
        {
            guessed = "too high";
            return guessed;
        }
        else
        {
            guessed = "correct";
            return guessed;
        }
    }
    // when execution reach this point, there is no return value.
    // The compiler do not know that execution will never reach this point.
}

Simply return once after setting value of guessed

class GuessNumber
        {
            public int number;
            public Random Rand;

            public string randNum()
            {
                int randomNumber = Rand.Next(1, 9);
                string guessed = "";
                while (guessed != "correct")
                {
                    if (randomNumber > number)
                    {
                        guessed = "too low";
                        
                    }
                    else
                        if (randomNumber < number)
                    {
                        guessed = "too high";
                        
                    }
                    else
                    {
                        guessed = "correct";
                        
                    }
                }
                return guessed; //simply return once after setting value of guessed
            }
        }