Email from text box with formatting

[viiktoryia]

I have a template for the email contained in a shape in an Excel sheet, and the text in this Shape also contains bold formatting.
However, when I run my macros to create an email from this template it does not keep the formatting.
Please advise what can be changed for below code to generate the email and keep the format the same as in Excel shape.

Dim OutApp As Object
Dim OutMail As Object
Dim subject_name As String
subject_name = "DELIVERY ORDER " & MainWB.Sheets("Overview").Range("B3") & " ETA " & Format(MainWB.Sheets("Overview").Range("B4"), "DD-MM-YYYY")

Set OutApp = CreateObject("Outlook.Application")
OutApp.Session.Logon
Set OutMail = OutApp.CreateItem(0)

On Error Resume Next
With OutMail
    .SentOnBehalfOfName = MainWB.Sheets("To send").Range("C2")
    .To = email_list
    .CC = MainWB.Sheets("To send").Range("C4")
    .BCC = ""
    .Subject = subject_name
    .Body = MainWB.Worksheets("To send").Shapes("TextBox 2").TextFrame.Characters.Text
    .attachments.Add TempFilePath & TempFileName & FileExtStr
    .display