- “Vulnerable Petra is way hotter than Ice Queen Petra”
- — JR
Petra and Jane meet when Jane is assigned to Petra's legal case regarding the suspected murder of Petra's sister, Anezka. Jane, also known as JR, came into the case with the belief that Petra was guilty of the murder. Later on she begins to believe that Petra isn't guilty after all and tries her best to prove Petra innocent.
Petra starts to catch feelings for JR, having dreamed of them kissing, and tries to hide her crush from JR. When JR believes they are being followed by the people who blackmailed her, she kisses Petra to pretend as if she can seduce Petra in order to use her to Jane's advantage. Petra visibly enjoys her kiss with JR and starts to become closer to her. Things escalate between them leading to them sleeping together. JR claims that their tryst was a one-time thing, even going as far as to tell Petra that she isn't her type. JR later discloses to Petra that she has a date to which Petra becomes jealous and follows her to see what JR's type really was. While spying on JR's date, Petra chooses to leave but accidentally reverses into the car behind her. JR sees and goes over to confront Petra on stalking her. Petra tells JR what she really feels for her and leaves. Later that night, JR shows up at Petra's room telling her that she enjoyed her "romantic gesture". They kiss.
JR and Petra start to date and eventually JR meets Petra's daughters and Jane and Rafael. In the season finale, JR learns that Petra lied about killing Anezka. JR is furious; she had given up her job to prove that Petra was innocent only to learn she was guilty all along. JR breaks up with Petra, storming out of the apartment. Later on JR gets word from Petra's former assistant that someone is coming after Petra. JR rushes back to the apartment to find Petra and sees someone pointing a gun at Petra. JR shoots the intruder and saves Petra's life.
- Petra – “I love you”
- Jane – “I know”
- — Goodbyes
It turns out Petra's stalker was Miloš, Petra's criminal ex-boyfriend and former legal husband whom she married under duress. JR only shot him in the arm, but Miloš reveals that he bought Luisa's shares of the hotel and now owns 2/3, which he offers to Petra if she lets him go. When Petra hesitates, JR is angry and leaves, saying this is why she ended things with Petra. Petra later gets Miloš arrested and tries to convince JR to reconcile. Jane comes to get her stuff and says that she doesn't trust that Petra's truly changed and leaves. After giving JR some space for a while, Petra tries to text her to see if she'll respond and she does. They start talking again over text and finally JR agrees to go out on a date with Petra. Simultaneously, Petra deals with Magda's return and interference in her life. Magda handcuffs herself to Petra, who has to bring the literal baggage of her mother along with her to meet JR. At Jane's door, Petra says that yes she has a lot of baggage and a past, but she has changed and will continue trying to and wants JR to be a part of her life. Magda tries to spill of Petra's past secrets to repel JR, but to no avail. JR gives in, as she missed Petra and they kiss and make up, with Magda still handcuffed to Petra. At The Marbella, JR brings an axe and chops the handcuffs so that Petra and Magda are finally separated. JR and Petra walk in the hotel, kissing and happy.
After reuniting, Petra starts to initiate sex, but JR says she wants to take it slow after what happened. Petra agrees, but they fight when JR sees an e-mail from Petra to Miloš on Petra's phone. Petra swears she didn't write it, but JR feels overwhelmed and leaves. After getting proof that it wasn't her, Petra seeks out JR and shows her. Despite this, JR tells Petra she feels like she can't trust her. Petra responds that she'll have to work hard to earn back Jane's trust then, because it's worth it. Some of that effort includes being a part of Jane's life now, as she works as a bartender and hangs out with her friends. Jane doesn't think Petra's much of a gay bar girl, but Petra wants to prove that she is and enlists Jane Villanueva's help to make a good impression on JR's friends. JR's best friend, Leona, doesn't like Petra because she broke JR's heart and Petra thinks it's understandable given that Leona's just being loyal. JR later gets mad about this, but Petra says that it's okay and that Leona's a good friend. All of Petra's efforts result in JR wanting to have sex again, as she now feels comfortable to do so.
- “I used to think my worst nightmare was turning into my mother but now I know... it's living without you”
- — Petra
- “I'm not into being a straight woman's guinea pig”
- — JR
- “I really, really like you. A lot”
- — Petra
For a long time fans have head-canoned Petra as bisexual, very commonly shipping her with Jane Villanueva. With such loud support for a bi character the writers decided to lean into that by giving her a female love interest. The love interest came in the form of the newest lesbian character, Jane Ramos. Coincidentally, or not, naming Petra's new love interest Jane is a nice nod to the Jetra ship. Petramos is one of the more popular ships in the Jane the Virgin fandom.