Is 'Sister Best Friend' A Popular Romance Trope?

“You have no idea what you’ve done to me. I’ve been replaying every sound you made, every way you came apart for me.” His grip tightened. “I’m not letting that go. I’m not letting you go. Fuck the friendship. I want you.” I let out a little gasp. His thumb rubbed across my lower lip. “I don’t just want to fuck you—I want to keep you. You’re my favorite sin, and I’ll commit it again and again until you understand you’re mine.” His lips twitched a little. “You’ve always been mine, Savannah.” ——- Her sister is marrying her ex. So she brings her best friend as her fake fiancé. What could possibly go wrong? Savannah Hart thought she was over Dean Archer—until her sister, Chloe announces she's marrying him. The same man Savannah never stopped loving. The man who left her heartbroken… and now belongs to her sister. A weeklong wedding in New Hope. One mansion full of guests. And a very bitter maid of honor. To survive it, Savannah brings a date—her charming, clean-cut best friend, Roman Blackwood. The one man who’s always had her back. He owes her a favor, and pretending to be her fiancé? Easy. Until fake kisses start to feel real. Now Savannah’s torn between keeping up the act… or risking everything for the one man she was never supposed to fall for.

For years, eighteen-year-old Mia has been secretly in love with Ethan — her older brother Jake’s twenty-two-year-old best friend. To Ethan, she has always been the little sister he promised to protect. But with their parents away for two weeks, Mia refuses to stay invisible any longer. Determined to make him see her as more than just Jake’s sister, she begins spending more time around him, testing the boundaries of their long-standing friendship. Ethan tries desperately to resist the growing attraction, torn between his loyalty to Jake, his own responsibilities, and the undeniable pull he feels toward Mia. As the days pass and emotions run high, the careful distance between them starts to crumble. One unforgettable night and everything changes. Now the line has been crossed, and neither of them knows if their friendship or their family will ever be the same again.

Olivia had never thought she'd see Aiden other than her sister's best friend who is constantly a thorn in her shoes, but after they accidentally made out, things changed between them. Aiden is that one man she should not want. He's forbidden. Off Limits. A certified man whore who doesn't do relationship. And what's worse? Her sister's best friend.

He is a 10 but he is a decade older than me, my brother’s best friend, a therapist who wants to counsel me and... he likes to hurt little girls like me. “What were you doing this morning?” “I was meditating.” He is right. I am a terrible liar. Aiden raised his eyebrows. “Is that so?” He waited for my answer, crossing his arms over his chest. I got distracted by the way his biceps bulged. He noticed me staring. I glanced down at my lap, twiddling my thumbs. “Y-yes, Doctor Aiden, I was meditating and I-I focused on my breath like you taught me—” “Why are you lying to me, Ivy?” My head snapped at him. “I-I am not lying.” Aiden tilted his head and my throat went dry when he said, “Then why did I hear your voice moaning my name when you orgasmed with your fingers inside you?" He is her first love. She is his best friend's little sister. Will a chance reunion lead to true love? I was a good girl. An honor student. A dutiful daughter, sister and a sweet girlfriend to my boyfriend until I found him in my best friend’s bed. I didn’t want goody-two-shoe nice boys who gave me empty promises. What I wanted was a man who wouldn’t hurt me. When I found my brother’s best friend, Aiden Stone, with only a towel around his hot Greek body dripping wet from a shower, I decided that what I wanted, what I had been wanting for years, was him. The only problem? He is a decade older than me, my brother’s best friend, a therapist who wants to counsel me and... he likes to hurt little girls like me.

After her father walks out on their family for his secretary, seventeen-year-old Miley’s world crumbles overnight. With her mother barely holding it together, they move to a quiet suburb hoping for a fresh start. But peace is the last thing Miley finds. Because the boy next door? He’s a walking headache with a six-pack and a smirk. Shirtless. Arrogant. And totally infuriating. Their first interaction? He flips her off. Their second? He calls her “darling” like it’s his full-time job to get under her skin. She wants to hate him. She should hate him. But Jordan isn’t just Liv’s older brother—he’s a tangled mix of charm, mystery, and a past he won’t talk about. And worse, he’s seeing straight through her walls. As secrets unravel and sparks fly, Miley is forced to confront everything she’s running from: heartbreak, trust, and the terrifying possibility that sometimes the person you hate the most… is the only one who truly sees you.

“Some—body will see us he---re,” I whispered through gasps, afraid any teacher will catch us making out in the school’s hallway. “They cannot put the Alpha King in detention,” he smirked, burrowing his face again in my neck and gently sucking my lips until I bit my tongue to not moan loudly. “One day, I will mark you mine Serena!” the moment he said my sister’s name while pressing his lips against mine, I felt betrayed. .. Serena Majestic is the next in line to be the Alpha of her pack. Born to lead and has lived a perfect life with everything she could have ever wanted. Loved by her family ✅ A perfect mate ✅ Respected by her pack ✅ Pretty looks ✅ Dream wedding ✅ She was loved by everyone, except for her twin sister, Arlene Majestic, who she always regarded as the villain of her life. What happens when she suddenly wakes up in her twin sister’s body as the villain she once hated on the day of her wedding? Helpless, she is forced to watch her sister get married to her mate. Arlene challenges Serena to mend Arlene’s life. It was the only way for Serena to get her body back. Fighting every day to make her sister’s life better to get her life and body back was her only goal. But what happens when she falls in love with her sister’s mate in the process? What will Serena do when she discovers the shocking truth about her sister’s life? Will she succeed in getting her life back or forever struggle in her sister’s body? Read now to find out.