Yes, when you save it to database it link has a domain.
Create field as fallows:
- Data Type: long text
- Form control: Rich text editor
- All other settings are left as default
Then edit any page where this field is available. Update this field by inserting link to other internal page.
Display this field somewhere on live site on you MVC (Kentico 12 MVC) application. You'll see, that links contains domain.