For RTL Text Style to work as intended, you should use a configured theme to support RTL languages.
To configure a theme that supports RTL, do as follows:
Login to your UserGuiding panel and go to Themes under Customization.
Select an existing Theme to edit or create a new one.
Under the Typography tab, configure Header 1, Header 2, Header 3, Body Text to be justified to the right.
Save and publish the changes.