How do you know if the emails you send to somebody is going into their spam or trash pile?

Answer 1

Unfortunately, one cannot be entirely certain of whether one's emails are being received; at least, not through the email system itself. Depending on the precise nature of the email, there are a few ways one could use to check.

If one expects a reply to the email, for instance, then naturally receiving such a reply would imply that the message was received and not sent to a spam folder. One could ask for a verification-of-receipt message specifically when sending an email.

Another way to test whether messages are being received properly and not being sent to a spam folder is to use a confirmation email. Many Web sites use these: an email with a confirmation code or link is sent. If the recipient clicks said link, then they have received the message.