Asiento or Assiento: How To spell?
The word Asiento is misspelled against Assiento, a noun meaning "A contract or convention between Spain and other powers for furnishing negro slaves for the Spanish dominions in America, esp. the contract made with Great Britain in 1713."
Assiento has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings a & iento which should not be misspelled with single 'S'
Wrong Spelling:  a-s-iento  Correct Spelling:  a-ss-iento 
Find more incorrect spellings of Assiento to spell right way.