Mispelling or Misspelling: How To spell?
The word Mispelling is misspelled against Misspelling, a noun meaning "A wrong spelling."
Misspelling has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings mi & pelling which should not be misspelled with single 'S'
Wrong Spelling:  mi-s-pelling  Correct Spelling:  mi-ss-pelling 
Find more wrongly spelled words of Misspelling to spell it well.