Hello Carlene and welcome to our community!
You can book your ticket with our site, ItaliaRail28, from Rome to Messina. The journey has two parts: Rome to Salerno or Naples, which is a Frecce high-speed train, and then onward by Intercity train from Salerno or Naples to Messina.
Train schedules are generally released in six-month increments, so the schedule for next June won't be available until later this year or possibly early 2023. If you go to our Train Timetables page69 and click the blue "Follow" button on the upper right, you'll get notifications every time the national railway releases new bookable schedules.
Thanks for being a member of ItaliaPass!