She knew she would be happy to see him, but didn't know she would be this happy to see him. But it had been far too long, so much so that she had sometimes thought that Jack had been killed and wasn't simply helping to rebuild after the Daleks.
She tried to seem a little dignified, to react in a more mature way. But this was Jack. And he was someone she certainly didn't mind being like a child in front of. Someone she didn't have to hide anything from. Laughing a little, she launched forward, her arms tight around his neck as she pulled him close. After all, he knew that was something she was after. She had missed being held close by him and not in any sexual way. Yes she was attracted to him, and loved him dearly, but they both came to the unsaid agreement when they travelled that it wouldn't work. And they were both fine with that, happy to drown in the affection they could show each other in this way.