Hope someone can help, im starting laying a hardwood floor, my starting wall has a fireplace hearth in the middle of it, how can i nail boards on both sides and hope they join perfectly round the front of the hearth?

Why not start on the opposite wall? If that's not possible, I would be inclined to start in the middle of the room and work both ways. Also - don't forget to undercut!

I cant start on the opposite wall really, how can I start in the middle, i wouldnt be able to blind nail half the floor?

Basically, you screw a straight 2x to the subfloor and butt your groove against it. Start off towards the wall as you normally would with the tounges leading. Once that half is done, you remove the 2x, put in a spline which let's you butt two grooves against one another, and then take off towards the other wall, again, with the tounges leading.

I'm an amature / DIY guy, so if the pros contradict what I have to say, believe them.

Frame the fireplace but don,t nail or glue anything down. Then measure out from the wall on each side and snap a referance line{I almost always snap a reference line to keep everything going staight ]. Then use the reference line to make a line a full board out from the outside of the frame. you can start the first row off the front of the fireplace by gluing and nailing.Then you will have to make splines and turn the floor around and run back to the wall.The other way is to snap a reference line from the wall and measure back to the wall on both sides of the fireplace to snap 2 lines then start the floor on either side until you reach the front of the fireplace.but with that method if your calculations are off you might have to srcribe your boards going aroung the frame. In my opinion the fireplace is important because it is a focal point of a room. Lately all Ive been doing is going off the front of the fireplace with a full board because it looks the best and keeps the frames square to the floor and its not that big of a deal to turn the floor around. I hope I don,t confuze you with long post but I can never seem to keep it short. Good luck