Can't hack whatsapp??
I have (Kinda) done it before.
All whatsapp messages (Even ones you deleted) are stored on one DB named msgstore.db.crypt.
All that is needed to see the persons messages is to retrieve the DB and download crypt tool or something similar to decrypt to text.
You need a charge? oh sure, plug it in to my PC

done!
I done this a coupe of years back after discovering the DB and then, out of curiosity, trying to decrypt it.
Since whatsapp now also supports a web version, there is an easier way to do it with a phone in your possession.
Simply navigate to web.whatsapp.com, scan the QR code on screen from within Whatsapp > menu > whatsapp web.
The phone will then be permanently connected to the browser you launched Whatsapp Web on with no notification of your connection on the mobile device.
EDIT: I would just tap that again and tell her to piss of anyway
