She is in a relationship with a Christian man and she wants him to become Muslim so she can marry him

Praise be to Allah.

There are many ways of creating interest in Islam, such as reading the seerah (biography) of the Prophet (peace and blessings of Allaah be upon him), or reading about the miracles of the Prophet (peace and blessings of Allaah be upon him), or about his prevailing victories and the defeat of his enemies. One may also look at the beauties of Islam, or explain that the sharee’ah of Islam includes everything that is good, and that sharee’ah does not enjoin anything except that which is in accordance with reason and common sense, and it does not forbid anything without explaining what is wrong with it and putting people off it. For this reason people, Arabs and others, entered Islam voluntarily, without being forced. We advise this woman to put an end to her relationship with this Christian man which has lasted for so long and he is still persisting in his kufr. If he chooses Islam of his own free will, then he must be tested after that to be certain that he is sincere. He must also be told that if he goes back to Christianity after becoming Muslim, he is to be killed. (Because the punishment for apostasy in Islam is death. Whoever recognizes the true religion and enters it then leaves it, does not deserve to live. Hence the Prophet (peace and blessings of Allaah be upon him) said, “Whoever changes his religion, kill him.” This is what is to be applied if he is living in a country which is ruled by sharee’ah. The point is that this person should be informed of the seriousness of the matter. And Allaah is the source of strength.)