Not receiving notification for a particular contact on whatsapp I'm not quite sure if this problem exists with someone else, I couldn't find it anywhere on the Internet. 

There is a particular contact whose notifications I never receive. By notifications, I mean the ones that come on the top. I need to specifically open Whatsapp to check his messages. 

I'm able to see notification of other contacts, and he is able to see mines. Also he has checked by sending message to some other contact, and they do get a notification.

I don't know if there is a secret option to turn off notification for a particular contact, is there any way to fix it? I've already tried reinstalling Whatsapp.
You may have muted notifications for this contact. Press the menu button on your device (or touch the menu button in the top bar (action bar) if your phone has no menu button) And go down to "MUTE" then from there you should see an option to hide notifications. All you have to do is turn that off, and that contact's/group's notifications should start appearing again.