How do i get my code to return the the answer without the extra '' and ()

Pls, provide a more readable code listing the next time.

You can simply use format() method that each string object can perform.
This may be helpful.
https://pyformat.info/#simple

In your case it will be something like this:

return "The text contains {} alphabetic characters, of which {} ({}) are 'e'".format(len(new_string), total_e, percentage)