i will use the CryptPassword from WinSCP.ini on my .NET

I have writte a pprogramm with .NET in VB not in C#
I will connect to a normaly FTP with username and Passwort. I have a XML to create the Session.Option.
But i dont will write my Passwort in Plaintext in my XML. i want to use the crypt Password form the ini

my application say i cant convert string() to SecureString()
.SecurePassword = XLMRead_PasswordSecure

I'm not sure I understand your problem.
Did you expect that the password encrypted in WinSCP.ini file is encrypted using SecureString? It's not.