Claudia Severa to her Lepidina, greetings. On September 11, sister, for the day of the celebration of my birthday, I give you a warm invitation to make sure that you come to us, to make the day more enjoyable for me by your arrival, if you are present. Give my greetings to your [husband, Flavius] Cerialis. My [husband] Aelius [Brocchus] and my little son send him their greetings
I shall expect you, sister. Farewell, sister, my dearest soul, as I hope to prosper, and hail.
https://www.livescience.com/archaeology/2-000-year-old-rsvp-a-birthday-invitation-from-the-roman-frontier-that-has-the-earliest-known-latin-written-by-a-woman
Huh, their writing is a lot more formal and flowery than I thought. Interesting!