A symbolic ceremony is the promise of love between two people. It is the exact same as a regular wedding ceremony, including the exchange of vows and exchange of rings. The only difference is that it is not legally binding. You can opt to get legally married in your home country and have a symbolic ceremony in Rome.
If you prefer, your wedding guests don’t even need to know this is only a symbolic ceremony. About 30% of our couples decide to have a symbolic ceremony, and for them this is the actual wedding; the legal paperwork is then only a formality.