Is it permissible for a university student who works in a company where women wear indecent clothing and he finds it difficult to completely lower his gaze, to leave the job, relying on Allah to compensate him with something better, especially since the salary is essential to pay university tuition fees?

As long as you are in need of the salary and cannot find an alternative, dedicate yourself wholeheartedly to lowering your gaze, and limit your interactions with female workers to the absolute minimum. Seek help from Allah the Almighty, and increase your remembrance of Him, seeking His forgiveness, and supplicating Him to inspire you with guidance, protect you from the evil of your own self, purify your heart, safeguard your chastity, and provide for you from sources you do not anticipate, so that you may become independent of working in this mixed environment. Strive diligently to find another job. Know that striving against one's self in this situation elevates a person in ranks and joins them with the righteous. Al-Hafiz Ibn Rajab al-Hanbali said, "The best deeds are those most difficult for the souls." The Prophet, peace and blessings be upon him, said, "The worker among them will have the reward of fifty of you; for you find helpers in good, but they do not." And he said, "Islam began as a stranger and will return as a stranger as it began. So blessed are the strangers," who are "those who set things right when people have become corrupt."