So I looked up how to start the quest "How Little We Know" and it say I have to talk to the receptionist. Whenever I try to talk to her, nothing happens. I have gone through all of her dialogue options and nothing happens. Can someone help?

Never mind! I just did Bye Bye Love and the quest started soon after.

IIRC, it only opens up during the appointed part of the MQ by itself. HOWEVER, if you talk to Carlito in Vault 21, if you help him and his girlfriend, talking to her at the end of that quest will unlock How Little We Know.