What makes a man commit to one woman and not another?

I'm picturing a situation. A man goes through two marriages & divorces w/ women who could statistically be considered “higher risk” [details below]. Man then sees a "lower risk" woman, but keeps her at arms length. (He also appears to the "lower risk" woman to be angry/defensive re: relationships.) Does he consider the low risk woman as “not good enough” or has he given up?

Woman A ["higher risk"]
* high school drop out
* had 3 kids by 3 different guys by the time she began dating this man (they then have 2 kids)
* they connected after meeting in a bar [her w/ 3 young kids at home]
* has Borderline Personality Disorder
* “She was [sexually] the nastiest girl in three counties."

Woman B ["higher risk"]
* also had 3 kids by 3 different guys by the time she began dating this man
* Woman B’s friends warned this man that she had a history of cheating (which she repeated, leading to man initiating divorce < 1-year after the marriage began)
* “She was polite.” & “She payed her bills.”

Woman C ["lower risk"]
* college educated w/ state job
* one child
* “[She’s] a good person.”