Diarmuid does indeed like to talk, but that is understandable since he tends to trust everyone he runs into and wants to share with them the things that interest him or make him happy. He hasn't really learned yet that sometimes it's okay not to tell everyone everything ever.

Children...

"Everything should be okay, but I am going to talk to Lady Irene to make sure. It's just I would like to have the party outside and you can't really have a party outside right now! It might not be bad to have it in the temple either, but I would need to ask for permission to use it. It's a holy place!"