What is the ruling on shaking hands with one's fiancée, and which is a greater sin: shaking her hand or enjoying her company?

Summary: We have previously discussed the ruling on a man shaking hands with a non-mahram woman, and the limits of the relationship between an engaged couple. Handshaking and an open relationship with one's fiancée are not permissible in Islamic law because they are a means to corruption. It is not permissible for a Muslim to choose between sins; rather, he must abandon them all, for perhaps a small sin can be the cause of his destruction. The Prophet, peace and blessings be upon him, said: "Indeed, when a servant commits a sin, a black spot is marked on his heart. If he refrains, seeks forgiveness, and repents, his heart is polished. But if he returns [to sin], it is increased until it covers his heart, and that is the 'raan' which Allah the Almighty mentioned: 'No! Rather, the stain of their deeds has covered their hearts.'" He also warned against trivial sins. Anas, may Allah be pleased with him, said: "Indeed, you commit deeds which are finer in your eyes than hair, while we used to consider them among the destructive sins during the time of the Prophet, peace and blessings be upon him." The duty is to abandon all sins.