Throughout the series, is has been revealed that Pearl is in love with Rose. Rose called her "My Pearl" as well hinting the feelings may have once been returned.
In "Rose's Scabbard", Pearl reveals that everything she ever did was for Rose, and that she thinks she is beautiful and courageous.
In "Rose's Scabbard", Pearl tells Steven that she was Rose's sole confidant. Because of this, she feels incredibly hurt to know Rose did keep secrets from her.
In "Story for Steven", Pearl acts jealous by telling Rose that she can sing like Greg, most likely to get attention from her.
In "Rose's Scabbard", Rose calls Pearl "My Pearl". In return Pearl calls her "wonderful".
Pearl will often describe her status without Rose by describing other objects, such as her monologue in, "Rose's Scabbard": "That's just the Scabbard Steven, it held your mother's sword, nothing else could fit so perfectly inside. For all this time it's been.. incomplete.", she was actually describing how incomplete she felt after Rose had disappeared.
This had happened before in, "An Indirect Kiss", when Pearl was describing the brambles: "Look at them, they're a mess with out her guidance! Directionless...pathetic...clinging things!".
Pearl goes as far to state "None of you had what we had!" in "Rose's Scabbard"
In "Sworn to the Sword", Pearl's song "Do It for Her" reflects what lengths she went to for Rose as she tries to emulate the same thing within Connie for Steven.
In "Sworn to the Sword", she has a flashback where she yells at Steven as if were Rose, saying that (s)he is too important to die and Pearl must sacrifice herself.
Her exact words were, "Why won't you let me do this for you, Rose!?"
In "Sworn to the Sword", she teaches Connie to die for the person you fight for. Pearl fought for Rose and believes Connie should do the same for Steven.
In "Sworn to the Sword", Garnet says that Pearl retreated to her gem several times and risked her life in order to protect Rose, "She put Rose over logic, consequence and even her own life."
In "Sworn to the Sword", Pearl says, "Rose made me feel like everything,"
In "We Need to Talk", Pearl sits by the edge of the stage, jealous, because Rose is giving her attention to Greg.
In "We Need to Talk", Pearl and Rose fuse into Rainbow Quartz. Pearl uses this as a way of showing off the intimacy of her and Rose's relationship that she claims Greg will never have.
In "We Need to Talk", Pearl tells Greg that he is "just a phase", and that he doesn't really know Rose, out of jealousy.
In "We Need to Talk", Pearl watched Greg try to fuse out of jealousy.
In "We Need to Talk", it is debatable whether or not Pearl kissed Rose at the end of their dance (as they started to phase into white and glow), or whether she pulled her head close to her to fuse.
Her kissing Rose is supported by the fact that Greg thought that dancing and a kiss would fuse him and Rose.
This is contradicted by the fact that her head was closer to her shoulder.
In "Chille Tid", Pearl has a dream of Rose and her surfing together.
In this dream, she tells Rose to forget about Greg (showing that she is still jealous of Greg) and wants to be with her instead and travel the galaxy.
In "Sworn to the Sword", Pearl sings "On the battlefield when everything is chaos, and you have nothing but the way you feel, your strategy and a sword;". It can be assumed that she is listing things that would help her fight and are positive. When she says "the way you feel", she is most likely talking about how she feels about Rose and that that feeling would keep her fighting.
In "The Answer", Pearl is by Rose's side when fending off the other gems.
In "It Could've Been Great", Pearl said that Rose thought all life was precious and worth protecting.