Ai ga Areba!!

Keishirou and Hikaru are a couple famous for their togetherness. They're big jokers, and always end up by saying 'Ai ga areba!' which means something like 'as long as there's love!'. However, there's no romance, and Hikaru starts to get worried, watching other couples, that Keishirou doesn't love her romantically, but just as a friend...