This place is in a great location in principe real, located halfway between the Main Street of principe real and the barrio alto dining / bar area. It's also pretty easy to get public transport to Belem.
Talita helped us check in east which let us drop off our heavy bags straight from the train and was super helpful. She even left us a bottle of wine and non alcoholic drink which was thoughtful.
However the place isn't perfect- there are some things to be aware of when booking. The street is also very quiet, tucked away from the plaza that has restaurants, but within 1-2 minute walking distance of that area.
1) you will need ear plugs (it would be good if the air bnb provided them!) as you can hear every single movement from the apartment upstairs. And at all hours of the night.
2) the bed is a small double bed, so if you are two regular or large sized people, it will be really really tight.
3) there is no dryer if you are planning on washing and the washing machine is tricky to use.
4) there is some construction happening two doors down, so at 7am you might be woken with the noises, which tend to travel along the street but also through the walls.
5) it's expensive compared to other apartments, but we found it was cheaper than hotels.
Overall, I'd stay again, but be ready to be woken up by your neighbours!