This The Mentalist screencap might contain
bem vestido pessoa, terno, calças de terno, terninho, pessoa bem vestida, terno das calças, pantsuit, terno de calça, retrato, headshot, close up, and closeup.
The writers and actors don't want those two to get together. In fact, they laugh at the fãs 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 mais 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" or "they have a brother/sister relationship." But I've never seen anyone deny Jane and Lisbon's chemistry, so I won't focus...