How to avoid spam mail in vb.net HTML Format Mail

Imports System.Net.Mail

Shared Function sendMail(ByVal fromName As String, ByVal from As String, ByVal rcpt As String, ByVal subject As String, ByVal body As String, ByVal isBodyHTML As Boolean, ByVal BCCRcpt As String) As Boolean 'Returns True if send ok, False if errors
            Dim pEmailMessage As New MailMessage
            Dim pSmtpClient As New SmtpClient
            Dim pSmtpServer As String
            Dim pSmtpUser As String
            Dim pSmtpPass As String
            Dim pMailServerUser As String

            pSmtpServer = "chnexc001.gavsin.com"
            pMailServerUser = String.Empty
            pSmtpUser = "root"
            pSmtpPass = "draddots"

            pEmailMessage.From = New System.Net.Mail.MailAddress(from, fromName)
            If rcpt <> String.Empty Then
                pEmailMessage.To.Add(rcpt)
            End If
            If BCCRcpt <> String.Empty Then
                pEmailMessage.Bcc.Add(BCCRcpt)
            End If

            pEmailMessage.Subject = subject
            pEmailMessage.Body = body
            pEmailMessage.IsBodyHtml = isBodyHTML
            pEmailMessage.Priority = System.Net.Mail.MailPriority.Normal
            pSmtpClient.Host = pSmtpServer

            If Trim(pSmtpUser) <> "" Then
                pSmtpClient.Credentials = New System.Net.NetworkCredential(pSmtpUser, pSmtpPass)
            End If
            Try
                pEmailMessage.IsBodyHtml = True
                pSmtpClient.Send(pEmailMessage)
                sendMail = True
            Catch ex As Exception
                sendMail = False
            End Try
        End Function