It so happens that agents can't directly answer questions on crime rates for any area - they must direct you to the police or other sources. Here's a very good link with a map with colors indicating crime levels. Pretty cool! http://www.neighborhoodscout.com/nj/trenton/crime/
I see that you currently live in Middletown. May we please know why you are interested in Trenton? That would REALLY help us to figure out an area that might be a good fit.
For instance, if you are planning to buy something for your son/daughter to attend TCNJ ... well that changes what areas are good for that and I know them well.
Broadly, unless you have a really specific need to want to buy in Trenton, then I would really recommend against it. The property taxes are INSANELY high. A very close friend has a house in Ewing. It's worth about $225K and his taxes are $5500 A YEAR.
In Trenton it can be even worse. I was interested in a house on the river (an area called The Island) for about $130K and it's taxes were also $5300. On one of the best streets, Fisher Lane, a GRAND VICTORIAN - 6 BR / 3 Bath - $120K and $6000 in taxes. But ... a block away are row houses with boarded up windows and bad crime.
Most of Trenton REALLY got hit VERY HARD during the economic downturn. If you don't really know the area then it would be hard to imagine how far it fell in the last several years from where it was. Many stately homes on State St (no pun intended) went into disrepair.
Trenton is really a tragedy and has only very small pockets of areas that are possibly interesting, albeit with VERY high taxes. An area called HILLTONIA is perhaps the best. There is also an area right next to Business Rt 1 that is being gentrified, mostly by people from Poland but also some Czecks, etc. They have some AMAZING restaurants, food stores and meats. Yum!
Again - unless you have a specific reason to be interested in Trenton, you would be well-advised to buy just over the border in PA.
Would you please elaborate on what your needs are? Right now we can only guess and we'd like to help.