And what I know you're also asking, is Roma Termini safe at night?
In my experience, and the experience of everyone I know who has been here, Rome is one of the safer large European cities, even for walking at night. I feel far safer here walking around at night here than I do back home in the States. Even for Darcy, when she walks around at night, she doesn't have the same feeling of trepidation that people are trying to get her attention, or fear that people are following her.
Because Rome, and most of Italy in general, has dinner around 9pm, it's common for people to be out late, often past midnight. And this is especially common in the summer, where we've seen people jogging out past midnight because it's finally cool enough to do so.
Some attractions, like the Colosseum, even have a "night time tour" that starts at around 8:30-9pm or the Vatican "Night at the Museum Hours" that starts around 7 and end at midnight.
So don't be too surprised if you're out late and you run into tons of people; there's a lot happening at night!
You might have also heard about "no-go" areas, and while that's broadly untrue, there are stories of people being mugged or assaulted around Termini train station after it closes (around 1am). While this shouldn't concern many of you, if you are staying around the train station (as Darcy and I often do when we're taking an early flight, if this is you, I have an article here on decent hotels), there is a definite sense of antagonism bubbling in the area.
Because Termini is well-lit around the clock, it offers sanctuary for a number of people looking for a safe place to be. However, this can also mean there are those who are aggressive, verbally and even physically, to people sleeping there or walking by.
It's not a bad idea to avoid it at night, but for those of you with trains out first thing in the morning (like 6am), you shouldn't have any problems.
Other than that, I only recommend that you use judgement, just like anywhere else. Don't accept drinks from strangers, or open bottles. Don't start fights. Trust your instincts—it's much better that you not take a street that's making you feel a little afraid and take the long way around than for something bad to happen to you.