The label control has no built in vertical alignment.
The simplest way is to use 2 labels. One displays the border at the required size.
The other is autosize to fit display text and then centered over the other label.
This code assume 2 labels on a userform
Label1 formatted to size of holding border.
Label2 to hold text and center both vertically and horizontally.
.AutoSize = False
.Height = 100
.Width = 200
.Caption = "This is my" & vbLf & "label text"
.AutoSize = True
.Top = Label1.Top + ((Label1.Height - .Height) / 2)
.Left = Label1.Left + ((Label1.Width - .Width) / 2)