Lily Evans watches Remus and Sirius and doesn't understand how her werewolf friend could possibly think that Sirius doesn't love him. She can see those heart eyes and the biting of a lip, long, aristocratic fingers twitch and tap on the desk while a cool, collected, intelligent Remus is very still while reading a book, only glancing up occasionally to smile at Sirius, who quivers and smiles and never in Lily's life could she even begin to think or imagine Sirius Black being nervous, because it simply couldn't be.
But then again, there's James Potter and she'd rather pay attention to him than observe her friend's love life, even though she knows Sirius Black is impeccably, most thoroughly in love with Remus Lupin.