Gwen sees more than anyone gives her credit for. She is, largely, unnoticed by anyone except the few people who care about her; therefore she can pass anywhere unseen, her sharp eyes noticing what most people miss.
She sees the cold hatred in Morgana's eyes in the presence of King Uther and mourns the change in her mistress and friend. Where has the old Morgana gone? Gwen isn't sure that that woman exists any more. Perhaps the magic has banished her, never to return, instead replacing her with this woman made of ice and stone.
She sees the bond between Gaius and Merlin, one of friendship and family. The old man enjoys the company of the younger man more than Gaius will ever tell; Merlin relies on his teacher more than he will admit to. Gwen sees the trust between them and wishes she had a friend like that. For a moment she feels lonely and misses her father more than ever.
She sees the mixed feelings in Uther's eyes in the presence of his son. The king doesn't know or understand Arthur; simultaneously curious and annoyed, proud and disappointed. Arthur is cutting his own path through the maze of life and Uther doesn't understand why he needs to, and Gwen wonders if they will ever see eye to eye. They love and respect each other, of course, but Gwen knows that Arthur will be a better king than his father; perhaps Uther has had a glimpse of that future, and it frightens him.
She sees that Merlin is trying to hide something as he makes Arthur's bed one morning when she stops by his room to give him a message from Gaius. Curious, Gwen sneaks back in later and discovers the token she gave Arthur for luck over a year ago, hidden under his pillow. She relives one of her most precious memories – the first time he kissed her – and smiles to herself. Later Merlin and Arthur are pretending to spar in the courtyard and don't notice her; she sees the way that they have become brothers, and the loyalty they have to each other.
What Gwen sees more than she sees anything or anyone else is Arthur. She sees the satisfaction he takes in calling her "Guinevere", the only person to call her by her full name. She sees the way his blue eyes light up when he notices her and the smile that plays around his lips. She sees how keen he is to have a moment alone with her and the way he can never quite say the words he wants to. She sees his knuckles turn white when he clenches his fist to stop himself from punching any man who tries to flirt with her. She sees the love in his eyes when he thinks he has hidden it away, because nothing can come of how they feel about each other, at least for now.
But then Arthur reaches for her hand and kisses it, and what Gwen sees is more than love or loyalty or hate or friendship – she sees hope, and the future brightens.