What is the ruling on a girl refusing marriage before graduating from university, and what advice, from a Sharia perspective, should be given to the suitor and the prospective bride in this situation?

A woman should not refuse to marry a righteous man on the pretext of studying, for marriage and seeking knowledge do not contradict each other. If they do contradict, then if the knowledge is an individual obligation (fard ayn) such as learning about prayer and fasting, it takes precedence over marriage. However, if the knowledge is not an individual obligation and she feels the need to marry or fears falling into haram (unlawful acts), then marriage takes precedence.