If you've already set your style to display job titles in your Directory Widget, and job titles are not displaying for users that have this information on their profile, this is likely because it is not marked as their current employment. 

As a Platform Manager:
  1. Navigate to Core.
  2. Select People Finder.
  3. Search/select your user.
  4. Click the Contact Card tab.
  5. Under Business, click the yellow pencil/edit icon to the right of their Job Title.
  6. Check off "Currently Employed."
  7. Click Save.
User-added image

This can also be managed through Edit User Profile Data.
  1. Navigate to Core.
  2. Select Users > Edit User Profile Data.
  3. Search/Select your user.
  4. Under Business on the right, click Edit to the right of the user's Job Title.
  5. Check off Current Place of Employment.
  6. Click Save & Exit.
User-added image