Stefan and Caroline share their secrets and always help each other.
In Season Five, when Stefan lost his memories due to a spell, Caroline was the only person that he trusted immediately and he also blatantly flirted with her on at least one occasion, telling her she was "much hotter in person".
During Caroline's mom's funeral ceremony, Stefan overcame the doubts in his mind and realized that he had developed deep feelings for Caroline - referring to it as being potentially "something even better" than his previous romances, even if he could not quite define them - but after the service, he arrived at her address too late to tell her since she had already flipped her humanity switch in order to cope with her mother's death and in the belief that her love was unrequited. The relationship between the cured vampire doppelgänger, Stefan Salvatore and the vampire, Caroline Forbes. In Season One, Caroline felt an attraction for Stefan, but he rejected her immediately because he was interested in Elena. I remember how you told me that when I was ready for you, you would be ready for me. I think a part of me has been ready for this day since the moment I first saw you, the new mystery guy in the hallway at school. A hundred years from now, I will remember this moment for the both of us.She was the person who revealed to Stefan both that Elena was sired to Damon and that Elena had slept with Damon.Stefan, on the other hand, comforted Caroline during the emotional fallout of her sleeping with Klaus.Stefan makes an attempt to save her but fails due to the fact that Damon bailed at the last minute. Valerie casts a spell on Caroline which turns her skin to vervain making it hard for vampires to harm her.Caroline then discovers from Nora after she gives Caroline Stefan's old journal that Stefan was romantically involved with Valerie, a Heretic.They decide to attend The "Heaven and Hell" ball where they force Nora to siphon the spell off of Caroline after threatening Mary Louise's life.Stefan and Caroline then kiss and have sex for the for the second time.Stefan and Caroline team up against a new threat in Mystic Falls, The Heretics and while boarding up Caroline's house, the two share a moment.Caroline later gets kidnapped and taken by Enzo who was following orders from Stefan and Damon's mother Lily.