The Assassin's Heart is an enthralling character driven Thriller about an assassin who begins to question her allegiances when her own heart and emotions are on the line.

Delia straddles the line between consummate professional and romantic heroine and plays both extremes rather well. The first chapter shows how cunning and methodical she is when she pursues her target. She sneaks underwater in the Pacific Ocean as he catches a wave. Her actions are almost shark-like as she circles her prey, weakens him, and draws blood before pulling him under all unseen. It tells Readers all that they need to know about how Delia operates and why she is so highly regarded within the Organization that recruited her.

When she approaches her assignment with Alexander, she researches his history including interests, personality, and family. She doesn't approach him like a shark, hidden, inscrutable, and violent. Instead, she approaches him like a companion meant to say the right things and appeal to his values. She attracts him before she kills him. She's less of a shark and more like a praying mantis or a black widow spider, attracting her captive before destroying him. In fact, she is so effective at her job that it would be nice to see more of this side of her as a remorseless killer.

Mostly we see her when she realizes that her job isn't what she thought. She had a code in which she only killed people who were violent criminals, embezzlers, or friends of dictators, people who got away with serious crimes so she felt deserved to die. This code becomes compromised when she learns that one of her targets actually had a clean record and her handlers planted a phony felonious past so she would kill him with impunity. This realization that she had been deliberately used makes her suspicious of the Organization that trained her and took pride in her successes.

Her relationship with Alexander also becomes a deal breaker between her and the Organization. For the first time, she bonds with a genuinely good man and with whom she has fallen in love with. She can't bring herself to pull the trigger no matter how much her handlers order it. After she refuses, they go through extreme measures to break her, treating her just like she used to treat her targets. She is just prey to them, someone to be destroyed with no conscience.

Delia lived a life of violence that overpowered her enemies and tried to live without a conscience. It worked until her conscience overpowered her.