Question

why , always the north end of the compass points the direction of the magnetic field ?

Answer 1

because the compass needle is a magnet, and magnets align in the direction of the magnetic field

Answer 2

you have not seen the question carefully. I have asked that why only the north end of the magnet gives the direction of the magnetic field and not that whether compass is a magnet or not .

Answer 3

The north end of a magnet points towards the earth's magenetic south pole which we call the geographical north pole.
similarly, the south end of a magnet would point towards the earth's magnetic north pole which we call the geographical south pole.
just as a magnet's north pole points in the direction of the magnetic field, the magnet's south pole point's directly opposite to the field.

Answer 4

one should also consider the importance of convention here. people observed that magenets when left alone would point towards the earth's north pole(geographical). hence they called this end of the magnet(thats pointing to earth's north pole) as the north pole of the magnet.
Another convention is that we chose to say that magnetic field lines originate from the north pole to the south pole. one could have chosen the opposite too.