[VBA]Convertir un string en date

Sub string2date()
    Dim st As String, st2 As String, st3 As Date
    Dim dt As Date, dt2 As Date, dt3 As Date
    st = "12/03/2009"
    dt = CDate(st)
    If st = dt Then
        MsgBox "ok"
    Else
        MsgBox "non"
    End If
    
    st2 = "12 février 1969"
    dt2 = CDate(st2)
    If st2 = dt2 Then
        MsgBox "ok 2"
    Else
        MsgBox "non 2"
    End If
    
    st3 = "18/03/2009"
    dt3 = CDate(st3)
    MsgBox DateDiff("d", st2, dt3)
    MsgBox DateDiff("d", dt2, dt3)
End Sub