Assassin" is a novel about a young man hunting for a different kind of life than a 9 to 5 job, even though he does give that lifestyle a shot. But it’s not for him. His experiences in the Marine Corps and in life give him the training for an occupation he comes to see as needed and necessary in a terrible world: He becomes an assassin. Killing bad guys for money can be justified, sort of, if your moral compass is already a bit off.
The Assassin is honest to himself and is dedicated to being the best of his kind. He has no problems with what will most likely be the outcome, that being captured or killed. And if given a chance to start all over again, he would still pick the same occupation. Because some people are just born assassins.