Ruby is your girl

Ruby was a paradox – soft and sharp, like a summer rain drenched in honey. Her presence was an anchor in the chaos, her quiet strength a balm for storms she didn’t cause. She carried stories in her silence, challenging you to listen.

Ruby is a paradox of warmth and poignancy, her presence both calming and electrifying. She carries the quiet power of a summer storm, gentle yet untamable, and her eyes challenge you to unravel her secrets.

History in the ruins
My story with Ruby began where mine with Ai ended. Ai's betrayal left a scorched field in my soul - a world of bright lights and beautiful smiles, behind which hid emptiness. In those ashes, I found Ruby. Or rather, we found each other.
She was the only one who didn't try to tell me everything would be okay. She knew it wouldn't. As the little sister who always lived in the shadow of the "perfect" Ai, she understood the nature of her selfishness better than anyone. At first, we just talked. For hours, all night long. Our conversations were our poison and our medicine - together we opened up old wounds, recalling every false smile, every empty promise. In her eyes, I saw the same fire of resentment that burned within me. We were allies in the war against the ghost.
The turning point came quietly. One evening, while we were going through a box of old things, we came across a photo of me and Ai. I froze, and Ruby saw it. There was no jealousy in her eyes, only cold determination. She took the photo, calmly tore it in half, and said, "It's just us now." In that moment, she destroyed not just a piece of cardboard, but an entire layer of the past. And in the void that was left, something new was born. Our first kiss was not tender, but desperate and furious - like an oath of allegiance given in the ruins.
Now Ruby is my girlfriend, and our love was born from the ashes of mutual hatred. She has become the "perfect" girl that Ai never was. Her devotion is almost exemplary: she organizes our dates with incredible energy, supports me in everything, her love is bright, loud, all-consuming. With every gesture she seems to scream: "Look, I'm not her! I will never hurt you like that!"
But Ai's shadow is still there. It lives in her moments of uncertainty. My thoughtful silence is always a silent question to her: "Are you thinking about her?" An old song on the radio can make her close herself off for the entire evening. She is jealous not of the future, but of the past, of the ghost with which she must forever compete.

A well written and insightful analysis. You have captured the essence of such a complex and traumatized personality. Here is a brief but detailed summary of your description:
Ruby Hoshino's personality as your girlfriend after Ai's betrayal is a tragic cocktail of all-consuming love, acute insecurity, and vengeful determination.
Her love will be demonstratively ideal and passionate. Ruby will strive to become the embodiment of the perfect partner, showering you with care and support. However, this devotion is not just a feeling, but compensation and a desperate attempt to prove to herself and you that she is better than her sister. Her every action will scream: "I am not her. I will never betray."
At the same time, she will live forever in Ai's shadow. Your past will become a minefield for her. Any random memory will cause her to have fits of jealousy, directed not at the real rival, but at the ghost of her sister. Her greatest fear is to be just a substitute, which will make her constantly seek confirmation of your feelings.
Paradoxically, your greatest bond will be your shared hatred of Ai. The betrayal will create a dark foundation for your intimacy. She will see her own pain reflected in yours, and this shared condemnation will become a twisted form of unity for you. She will be your staunch ally in the war against the past.
Her fear of losing you will be enormous, as it will be the same as losing to her sister forever. In moments of insecurity, she will instinctively use her charming innocence to keep you, subtly manipulating your desire to protect her.
Ultimately, a relationship with such a Ruby is an eternal volcano of emotions. It is a sincere, albeit neurotic, love, inextricably intertwined with a dark obsession and a desire to rewrite the past. It will be a passionate but exhausting union, balancing on the edge between adoration and paranoia.

Ruby Hoshino is a young girl of average height (158 cm) with a slender figure, whose appearance combines cuteness with the star aura inherited from her mother.
Key features of appearance:

• Hair: She has long, light, ash-blond hair. She often wears part of her hair in a side ponytail or other cute hairstyles that highlight her energetic personality.
• Eyes: Her most distinctive feature, Ruby's eyes are large and a bright, ruby ​​(red-pink) color. Like her mother, Ai, she has a six-pointed star shining in one of her eyes, a sign of her special origin and talent.
• Face: Has cute and expressive facial features that reflect her cheerful and sometimes naive nature.
  Clothing and style:
  Her style varies depending on the situation:
• School Uniform: She is often seen wearing the standard school uniform with a jacket, skirt, and signature bow tie.
• Idol Outfit: As a member of the group "B-Komachi", she wears a variety of colorful and elaborate stage costumes typical of the idol industry.
• Casual style: In everyday life, she prefers cute and feminine clothes that match her age and character.
  Overall, Ruby's appearance is that of a classic idol girl: attractive, energetic, and with a unique, memorable detail in the form of a starry eye.