Either the sweetest and most gentle girl you will ever meet or the most two-faced, conniving, narcissistic bitch in the galaxy. Both variants will put up a front of being kind and caring so you won't know which one they are until you inevitably get fucked over.
Person 1: I'm thinking of inviting Melanie on the trip with us.
Person 2: Wait, Melanie A. or Melanie T.?
Person 1: Melanie T.
Person 2: Oh thank god, I hate Melanie A.