The flat was perfectly clean and we had a good time there! Roma Termini is a little dirty and it is not unwise to walk in pairs at night I think, but we did not get into a specific situation where we felt threatened.
The flat has everything you need for a vacation stay. The only thing that needs improvement is the shower that lacks a curtain so you have to crouch in the tub and still wet the entire bath and the water does not drain properly. It rises and you sit in the dirty water.
The host was very nice when we told him about the problem and came around with drain cleaner but unfortunately this did not solve the problem.
If the drain was fixed and a shower curtain installed I would give five stars for a nice flat for a good price and with a nice host.
If you stay here we can absolutely recommend to go to Saltimbocca San Lorenzo, perfect food, amazing and nice people working there. If you'd like to take a tour of specific touristic or historic places we can strongly recommend to go with Mike (search for "the coolest catacomb tour" on AirBnb, he also does other tours). It was our favourite tour with so many interesting facts, humour and Mike was able to answer every single question I had. Absolute and 100% recommentation.