Very commonly, dating couples lose track of their ultimate goal. Often dating becomes goal and couples struggle to keep a relationship going they know isn't working simply because they feel the need to be dating someone.
Dating is a time to get to know someone in order to decide whether the other person would make a compatible spouse in a marriage. If things are working out well when you are trying to impress the other person, what do you think life would be like if you married and the drive to impress diminishes? I can guarantee that life will get worse.
The book of Proverbs is primarily aimed at teaching young men the things they need to know to succeed in life. Among those teachings are observations about what type of woman makes a good wife and the many types of women who make poor wives. One observation that was so important that it was repeated four times is:
"Better to dwell in a corner of a housetop, than in a house shared with a contentious woman" (Proverbs 21:9 see also Proverbs 21:19; 25:24; 27:15-16).
A contentious person is someone who is never happy with the way things are. They tend to complain, hound and nag to get others to change because very little is ever good enough to please them. I would think that if she shows little signs of being happy and content now, you would be signing up for a life of misery later if you married her.
Dating is also a time of coming to know and understand the person you think you might marry. If she isn't making much progress toward understand you, then you need to ask yourself why. My guess is that she is too wrapped up in her own perceptions of the world to be able to see things from another person's point of view. That, too, is not a good quality in a potential wife.
When dating you need to consider who a person is, not who you hope they might become. People do change and grow. You will be changing and growing as well. But if you aren't starting from a common ground, you aren't likely to grow together. You need to pick a woman you would enjoy living with as she is right now. If you aren't happy being with her several hours each day, it will only become worse living with her.
Hard as this sounds, perhaps you should consider searching for a better companion.