I have seen a couple variations/guesses of Sarah's last name. In checking the microfilm copy of the original marriage records of Springfield, Mass., her last name is definitely HEALD. Check the old handwriting against the other names and known words. The top of the "d" is swung over the other letters, just as all ending "d"s are in the old records here.
I, too, have seen no evidence of any for-sure connections between Sarah Heald and John Heald, but would be interested in any new information on her.