Do I need wifi to receive Sara’s letters?

I’ve been sending letters to Sara hoping that she would reply back to me telling that her freakin’ pendant is broken.However,she has not replied to any of my letters.So I wonder…..do I need wi-fi to receive letters to the NPCs?

Yes. You need to exchange about 7 letters with another person, or people. Actually, you can just use wireless DS communication, iirc. So, if you’ve got a friend with a DS and III, just send each other letters.

Once you’ve exchanged that many, you should be able to get the 4 letters (per NPC) you need to start the various side quests.