Deleted text messages are hard to get back once they are gone, so check these places quickly.

1. Recycle bin of the Messages app

Samsung Messages: Menu (⋮) → Recycle bin – deleted messages are kept for 30 days.
Some other messaging apps have a Trash or Archived folder too.

2. Google backup

If backup is on (Settings → Google → Backup), SMS are included. They are restored when you set up a new or reset phone – not on the current phone without a reset.

3. Ask the sender

The other person still has the message and can forward or screenshot it.

Never lose one again

NotifySave saves the text of every incoming message notification, including SMS. If a message is deleted later, you can still read it in your notification history.

Note: NotifySave can only save messages that arrive after it has been set up.