Siena is a woman whom George dates in "The Face Painter."
George is on a date with Siena discussing the history of toilet paper. She is very fascinated by the conversation, which leads George to consider if he is in love with her. He later decides he will in fact tell her he loves her. On another date, while listening to a New York Rangers playoff game on the radio, and mentioning that he could've gone to the game but didn't want to break their date, George confesses to Siena that he loves her. Siena replies that she is hungry and that they should get something to eat. Devastated, George decides to end the relationship.
While Kramer is at the zoo to apologize to a chimpanzee that he got in an altercation with, he learns that Siena doesn't hear well out of her left ear. George thinks that she must not have heard his confession of love, and resolves to tell her again. On their next date, George turns her head towards him, and once again tells her that he loves her. Siena responds that she heard him the first time.