I would give this five stars strictly for the fact that it made me laugh out loud more than once.
The hero and heroine are a cute couple. As with the first book, the major conflict is internal with the heroine not wanting to give her heart to a man who she believes can never love her but intends to treat her as a weak possession. Her fears are well-grounded as the hero has roped himself off from those he cares about to protect them from his life as a spy. Plus he does not understand that women need more than protection.
While the romance builds slowly and with satisfying heat, I must say that even with the final resolution and implied HEA, I felt some discomfort that the heroine would ever get “all” of her hero. He did seem to be trying, especially with his sister, but he expected to keep his secret life as a spy mainly hidden. And not for nothing, given that he was the sole direct heir, his past and expected future participation in covert affairs makes him seem a little selfishly reckless. There are other ways to imperil those you love through risk taking other than immediate bodily harm.