Is it permissible to marry a Christian nurse with the intention of her embracing Islam and earning reward, achieving the happiness lacking in the first marriage, and avoiding the sins resulting from mixing with her at work, taking into account the possibility of losing current family stability?

It is permissible to marry a chaste woman from the People of the Book; in fact, it is commendable if her conversion to Islam is hoped for. If you can be just between her and your first wife, then do so. Otherwise, seek a righteous husband for her. Beware of being alone with her and lower your gaze from unlawful things, for that is one of the most important reasons for a husband's contentment with his wife. Remember that affection between spouses requires patience, overlooking mistakes, and focusing on the good aspects, in accordance with the Prophet's (peace and blessings be upon him) saying: "A believing man should not hate a believing woman; if he dislikes one of her characteristics, he will be pleased with another." Beware of rushing after fleeting desires, for what is intended may not be achieved, and you may discover faults that were not anticipated.