You have an extra space at the end. Fastest fix would be to trim it off your string before returning it, another option would be to overwrite the words in the array and use .join() on it, that way you won’t need to create that many intermediate variables.
While it’s not required, you can benefit greatly from the “helpful links” in each of these challenges. They refer you to the built in methods that simplify many of the issues you encounter in the challenge. e.g “Array.prototype.join() joins all elements of an array (or an array-like object) into a string.” Add a separator argument (’ ') and it returns a string with the supplied separator between each element. This means no extra space to deal with at the end of the string.