How do I create the swigly red line in a ricch text box

So I’m working on this text editor using a form with a rich text box, the spelling d other function work fine. However I would to add a function that underlines any misspelled word in ref in the rich text box and blue for any grammar mistake just like office does, I had thought to use part of the spelling checker as code for this but it does not work

So I’m working on this text editor using a form with a rich text box, the spelling d other function work fine. However I would to add a function that underlines any misspelled word in ref in the rich text box and blue for any grammar mistake just like office does, I had thought to use part of the spelling checker as code for this but it does not work

    errors = .SpellingErrors
Else
    errors = .GrammarErrors
End If

For Each errorRange As Word.Range In errors
    errorRange.Underline = Word.WdUnderline.wdUnderlineSing