Parramatta is very safe- the police are around all the time. You get stuff in any big city but Parra is no worse and much better than many other areas. I have never has a problem in the twelve years I have been here. Some rubbish about car break ins at Westfields online but I have never seen it myself or heard of it from anyone I know. The local kids are very respectful and not rowdy.
It is very safe but like any large city there will be some issues. Mostly it is low level stuff or bikies around Merrylands, not actually Parramatta itself. Parra is full of Asians and Indians and they are quiet communities generally. Parramatts does not have any specific issue with late night fighting or high rate of theft unlike the Sydney CBD.