I remembered the song Twin Soliloquies from the musical South Pacific, in which we hear the unspoken thoughts of both the man and the woman, each silently wondering whether the other feels the same way as they do. She muses ‘We are not alike, probably I’d bore him’, whilst he is thinking ‘What will be her answer? Do I have a chance?’ Here we may be looking at a similar scenario… or does ‘how am I to know’ merely reflect her reaction to an unfamiliar menu?!