You wont be able to use the Security assist forgot password behavior for this.
You will need to create a new page with a form to collect the display name and display name.
Add a recordset that will filter the users table on the entered email and display name to return the correct record.
add the Universal Email behavior to the page, set the to address to use the email address form the recordset, for the body, uncheck the option to use a file to manage the email, and click the DW Edit button to design the email body, and use the password recordset binding to add the password to the message body.