Is it permissible to break off an engagement after one's desire for the betrothed girl has waned and her academic performance has declined, along with the fear of falling into sins if the engagement or marriage to her continues?

An father should not prevent his daughter from marrying on the pretext of her studies, as this may lead to temptations that could cause her to fall into haram (forbidden acts), which is a dereliction of trust. It is forbidden for a father to prevent his daughter from marrying if she needs to and a suitable suitor proposes to her, in accordance with the Prophet's (peace and blessings be upon him) saying: "If someone whose religion and character you approve of proposes to you, then marry him. If you do not do so, there will be tribulation on earth and widespread corruption," and his saying: "Do not delay three things: prayer when its time comes, a funeral when it is present, and a single woman when a suitable match is found for her." If the woman is chaste and adheres to her religion, there is no reason to hesitate to marry her, and love grows after marriage. The issue of love before marriage and pre-marital conversations is an alien concept to Muslims, and its harms outweigh its benefits, especially if it involves forbidden acts.