display text multiline which consist empty lines in between - in a textbox on a userform

See if this helps:

Private Sub CommandButton1_Click()
Dim fso As FileSystemObject
Dim ts As TextStream

TEXT_FILE_PATH = ActiveWorkbook.Path & "\Data\Tekst\Diverse tekst\ekstra toiletter.txt"

Set fso = New FileSystemObject
Set ts = fso.OpenTextFile(TEXT_FILE_PATH)

Me.TextBox1.Text = ts.ReadAll

ts.Close
Set ts = Nothing
Set fso = Nothing

End Sub