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Bully Romance

The Cruelest Vow: A Dark Enemies-to-Lovers Romance (The Black Harbor Series Book 4)

Zara Molin

Book 4 in the The Black Harbor series · Reading order →

SpiceDarkness

How we rate spice & darkness

  • Kindle, paperback & audiobook on Amazon
  • Spice & darkness rated — content warnings listed below

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Why we recommend it

A vow forged in cruelty anchors this fourth Black Harbor entry, where enemies are bound by something neither chose and obsession festers beneath the hatred. The tone is dark and sophisticated, the stakes high, the chemistry combustible. Expect a morally grey hero, a heroine who refuses to surrender, and a slow burn toward dangerous devotion. Recommended for readers who love enemies-to-lovers steeped in vengeance and possessive heat.

At a glance

The Cruelest Vow is book 4 in Zara Molin’s The Black Harbor series. It rates 4/5 for spice and 4/5 for darkness, mid-range for bully romance: of the 419 bully romance books we rate, 9% score lower for darkness and 6% lower for spice. Tropes: forced marriage, bully and revenge. 2 content warnings are listed below, hidden until you tap.

Book details

Published
June 2026

The Cruelest Vow spice level

The Cruelest Vow is rated 4/5 for spice on Readark’s scale: explicit and frequent, meaning multiple detailed scenes, with heat central to the story. Its darkness rating is 4/5: heavy, meaning sustained cruelty, trauma or non-consent central to the relationship. How we rate

The Cruelest Vow content warnings

We list 2 content warnings for this book. They stay hidden until you tap, so you can check without spoilers.

Content warnings (tap to reveal)
  • Emotional Abuse / Gaslighting
  • Graphic Violence

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