Eid Mubarak.. Plz download following zip and extract in PC.
Dev-Host - Root_G_Pro_KitKat.zip - The Ultimate Free File Hosting / File Sharing Service
Install LG Drivers
Enable USB Debugging
Connect to PC, select LG Software
Click Run.bat file from above extracted folder. Set will boot and it will go into Stock Recovery of LG
Choose option "apply update from ADB" (Navigate using volume keys, and select Apply update from ADB by pressing power button)
Keep pressing any button on run.bat screeen. (It will say press any key to continue so you have to press 2 or 3 times, this screen will disappear.
Now you can remove cable from your mobile and reboot it. It will be rooted.