mac-app-store-submission-guide.md: typo correction

docs/tutorial/mac-app-store-submission-guide.md

@@ -7,7 +7,7 @@ limitations of the MAS build.
 ## How to Submit Your App
 
 The following steps introduce a simple way to submit your app to Mac App Store.
-However, these steps do not ensure sure your app will be approved by Apple; you
+However, these steps do not ensure your app will be approved by Apple; you
 still need to read Apple's [Submitting Your App][submitting-your-app] guide on
 how to meet the Mac App Store requirements.