Anita needs our book help! Oh I LOVE reclusive broken Heroes and the heroines that soothe their souls!!
There’s one that I can think of (though I don’t remember if he was an enforcer) and that was Madeline Sheehan’s character “Dirty” in her Undeniable series (and we see his story with Ellie – though I don’t remember her being so much “sweet” as more like… a strong heroine). Still, this is my guess, or at least a guess with a very similar trope which is Unattainable. I LOVE this trope, and in fact, here’s my 4.5 star review of that one. 🙂