When a user buys something with PayPal, they receive an automatic email about the purchase, if someone does it by the default tpv, they don't receive a confirmation email, and I have to send it manually. Is there any way to send it automatically just as PayPal (when they order anything).
This should actually be working.
Can you check if your cron is set up correctly? In addition, check the
core_email_queue table in the database. If you find entries of orders that have long since happened there, it's a sign that your cronjob does not work.