Output of Brushless ESC for controlling Brushless Motor
But as mentioned ESC is of 40A and motor is of 30A then at 2ms pulse
  ESC might sending pulse to Motor of the range of 40A (I doubt) then it
  should damage motor?


The "40A" figure is the peak current that the ESC can provide should the connected load (the motor) demand that current. If the output voltage of the ESC and the motor are compatible then a 30 amp motor will only take 30 amps under full-load conditions. 

It may take more than 30 amps under stall conditions but that is a different situation outside the scope of this question.