Best to unlock by getting grabbed by Andrea, in order to make sure you get this first try be sure to have a defense item.
Jeniffer can be hit up to 4 times. You will have to be hit 4 times in order for the stalker (Andrea) to grab you.
After when she grabs you, there will be a quick time prompt for you to press A repeatedly and then press X to stab her.
After you finish the prompt the achievement should unlock.
(Note that if you don’t have a defense item there will be no prompt for when she grabs you and you will be killed, therefore you will have to try again after the game loads back up to your checkpoint.)