The sent message is not in "sent".

Hi. I once wrote a letter to a person and then moved the letter to the trash. Some time passed, and I decided to resume correspondence with this person, click “reply” to the letter in the trash, wrote, sent, and… I don’t see it in the “sent”, for some reason it is grouped with the other emails in the trash. Can I now know if the message has been sent? I’m sorry if I was unclear, English is not my first language.