After their plan to capture Red John goes horribly wrong leading to the gruesome death of CBI Director Wainwright on The Mentalist season 4 finale, Teresa asks Jane if he's OK. He tells her he's fine and then he takes her hand in his as the two deal with the latest of Red John's horrors.
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.
Jane: I was hoping to dazzle you all with my uncanny detective skills, but you forced me, you forced me to reveal the humdrum facts and point out that you have blood on your shoes, Heather. Lisbon: Can you step out of your shoes ma'am? Jane: Stop the presses! That's the phrase right, stop the presses? Always wanted to say that.
Patrick: You don't like the way I drive, you despise it. Teresa: You drive way too fast. Patrick: I drive just fast enough. You hate not being the one in control and yet you're willing to overcome your irrational fears to cheer me up. That's a beautiful thing, Lisbon. Thank you, I'd love to drive. Teresa: Never mind.