This The Mentalist screencap might contain
invernadero, jardín interior, calle, escena de la ciudad, entorno urbano, configuración de la escena de calle, ciudad, urbano, ramo, ramillete, ramillete de flores, and ramo de flores.
The writers and actors don't want those two to get together. In fact, they laugh at the fans that want them to. Which personally I find a bit rude, but I won't get into that. Anyway, their reasoning for them not getting together (at least right now) is "they have más of a brother/sister relationship."
I'm sorry, but every time someone is trying to make an argument for why two people shouldn't be a couple, it's always either "they have no chemistry" o "they have a brother/sister relationship." But I've never seen anyone deny Jane and Lisbon's chemistry, so I won't focus...