Right up there with "definitely" is a completely SEPARATE issue.
And that is, why is it so hard to spell "separate"?
W. O. W. to the rescue!
Two clues, depending on how your brain tends to work, might help you.
1) If you can't spell "separate" correctly it means your spelling is sub-par.
2) Separate has four vowels: two e's SEPARATED by two a's. This should eliminate the tendency to spell it as "seperate." Ewww...that makes me shudder just to type it :-)
hat tip: annie w.