How do I ensure she marries me?

I am trying to figure out how to get married to my girlfriend, but she has been promised to someone else in an arranged marriage. We have been together for two years and our parents know about this, but her family is not okay because of my financial situation. We spoke about this and, at first, they agreed to give me time to save some money. They changed their minds after someone with better prospects approached them and asked for their daughter’s hand. I don’t know what to do. My girlfriend says she is breaking up with me because she can’t go against their wishes, and I have no way of improving my financial prospects quickly. Is there anything else I can do to convince them all to change their minds? We genuinely love each other, and I don’t want to lose her.
You may love each other but, as an adult, your girlfriend is making the decision to go by what her parents want for her. She is legally allowed to marry anyone she chooses to and has decided to end her relationship with you instead. What this implies is your financial condition may have no bearing if she has already made up her mind to marry the person her parents have selected. If her parents aren’t willing to give you time or reconsider their choice, it doesn’t seem as if you can do anything other than accept that this relationship has no future. It takes two people wanting the same thing for it to work.

How can I stop being intimidating and build lasting relationships with women I date? They say they can’t be with me for too long because it is too intense.
Ask for more constructive feedback, take what they say seriously, and take a break from dating until you have a better idea of what aspect of your personality needs to change. Also, think about the kind of people you are going out with, because you may not be the problem at all.