Theesm or Theism: How To spell?

The word Theesm is misspelled against Theism, meaning "Belief in God."

Word contains consecutive vowels 'EI' in between alphabets th & sm is misspelled as 'EE'
Wrong Spelling:  th-ee-sm 
Correct Spelling:  th-ei-sm 
Explore spell check of Theism to spell without errors.