Exactly that: You cannot force a woman to have an abortion.
You also cannot legally enforce a verbal promise; as others have noted, to make such a law would create ridiculous, dangerous, and unprovable (he said/ she said) circumstances. We don't have such laws for any other verbal promises, for all those reasons above, so I fail to see why we should make an exception in this case.
Written agreements are something different than a verbal promise, and even then, if you get a written agreement from your sweetheart that she will abort, you will also likely have to have it looked over by a lawyer to make sure that it is a reasonable agreement, otherwise judges will likely throw it out if they feel the person was coerced, lacked full understanding, or otherwise was entering into an unwise and unfair agreement (see pre-nup laws; even they aren't ironclad if a judge feels that they were unfair).
Additionally, relying solely upon a verbal promise as your ticket out of caring for your child that you helped create is simply dumb. People should be aware that people change their minds, that the decision to abort is exceedingly complex, and if they aren't aware, they are idiots. I don't think that we should make laws to protect stupidity.
Sex automatically comes with the
risk of incurring financial loss. You accept that risk everytime you consent to sex. Likewise, the cell phones might not have broken, even though there was the risk; maybe you were smart and put yours in an Otter box.
You have failed to make that case. How exactly is choosing to keep the child "relieving her of the responsibility" of breaking her promise? She has to pay dearly for breaking her promise to abort, namely, by carrying a child to term, by delivering it, and then by caring for it.
Maybe you are unclear of what "not aborting" entails. Generally, that means you carry a fetus to term, deliver it, and then (if you don't choose adoption), you raise it.
I find it incredibly strange that basically what it boils down to is that you don't think that Ana is being penalized enough. It's not that you don't understand that she's already being penalized for her decision; it's just not enough for you. And meanwhile, you are willing to let Harry off scot free for his responsibility in choosing to have sex in the first place. You are so concerned with Ana taking responsibility for her promise, that you are willing to completely let Harry drop all responsibility for choosing a course of action that resulted in the production of a child. Why are you not okay with one party not taking (what you deem to be) full responsibility, but are completely okay with the other party taking no responsibility at all?