Dim label1 As New Label With {.Parent = Me}
 
    Public Property TheText() As String
        Set(ByVal value As String)
            label1.Text = value
        End Set
        Get
            Return label1.Text
        End Get
    End Property

Dim subform As New Form2
Dim WithEvents rtf As New RichTextBox _
With {.Parent = Me, .Text = " der soll in ein label"}
 
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
 
   subform.TheText = rtf.Text
   subform.ShowDialog()
End sub