Cron only sends mail if there's output. Regardless of whether there are problems. The cron man page says,
When executing commands, any output is mailed to the owner of the
crontab (or to the user named in the MAILTO environment variable in the crontab,
if such exists).
But you read that.
To make sure there's always some output, put a line like "echo Hurray" at the end of your script. When you are sure all works as intended, take it out again.
You say changing MAILTO gave you output but was unsuccessful? I guess you initially redirected output (and errors) from the commands to /dev/null. So there was no output to mail. Once you leave output alone, mailing matters. If you don't set MAILTO, it will go to your user name on the machine where cron runs. Unless mail is locally configured to send it elsewhere, you can read your mail by typing 'mail' on the machine where cron ran.
You may want to elaborate, or tell us what you are trying to do.