On The Mentalist Season 4 Episode 24, "The Crimson Hat" just before Jane must pretend to kill Lisbon, he hugs her tightly and says he loves her. He later claims not to remember what he said due to the extreme stress.
In The Mentalist Season 2 Episode 11, "Rose Colored Glasses" after solving the case, Jane and Lisbon share a dance to the song "More Than Words. Lisbon certainly looks comfortable in Jane's arms.
In The Mentalist Season 1 Episode 23, "Red John's Footsteps" after declaring that he'd willingly die if it meant capturing Red John, Jane ends up shooting and killing the one man he knows could lead him to the serial killer in order to save Lisbon's life. Even Jane looks completely shocked by his actions.
Teresa leaving for D.C. was bad enough. Did Jane somehow make things worse? Will he finally man up and doing something to stop her before she marries another man?
Is Jane still trying to figure out whether Lisbon is headed to D.C. with Marcus Pike? He's certainly looking at her curiously on this episode of The Mentalist.