insert normal-style space between italics and end of paragraph marker

[macropod]

There is no 'Normal' character Style; 'Normal' is a paragraph Style, so you can't apply it to a single character in a paragraph. Presumably you want something like:

Sub Demo()
With Selection
  .Collapse wdCollapseEnd
  .Text = " "
  .Font.Reset
End With
End Sub

or:

Sub Demo()
With Selection
  .Collapse wdCollapseEnd
  .Text = " "
  .Font.Italic = False
End With
End Sub