Alfred is listening to Dick complain about his costume, but finds it amusing, due to the contrast with how serious Bruce was. He's pretty much smiling through this whole thing. 

Allred requires the tone of amusement while responding to Dick, give the sense that while this is happening that you're smiling, while maintaining that polite more subdued tone of his. He has an English accent, but if you want to go Scottish like the Nolan films/TellTale game has done, that's fine.