Answer: manipulation, psychology and the way the emails are written
Step-by-step explanation:
Spam senders always have various email addresses because the email providers learn of their illegal practices and shut down their accounts. However, nothing stops the spammers from making new accounts either on the same provider (if they are not IP blocked) or on a new one from the many available on the Internet. Furthermore, victims are gullible and some are unfortunately not computer-literate, so they believe the scams are true and genuine.