Nimbasa City, the house behind the Pokemon Center, top floor, talk to the old woman with a Pokemon that you have had for a long while (Starter or Lucario if you have it. Either would be your best bet) in your first party slot, and she'll give you the Soothe Bell.
Hmm she said I'm really connected with them but didn't give me anything.. What gives?
What Pokemon did you have in the first slot of your party? If anything, call Bianca and check that Pokemon's Friendship level (She'll tell you different phrases based on it's Happiness Level), and make sure it's really high, then talk to her again. Simplest way to make it higher is to just run around with it. Battling and winning helps a LOT too, and there's a girl in the Name Rater's building that will give your Pokemon a Massage that'll make it's happiness go up as well.