A Christian woman has the right to ask for a dowry from her Muslim husband

Firstly, we would like to thank you for your question. Secondly,
before we discuss the matter of your right to the mahr or dowry, we should discuss
the matter of marriage itself. A Muslim man is permitted to marry a chaste woman
from the People of the Book (see Question #689
and #2527), and she is judged according
to her situation at the time of marriage: has she given up her former promiscuous,
immoral ways or not? If she is chaste and pure, it is permissible for him to
enter into a marriage contract with her, and in this case, the dowry is her
undeniable right. In order to resolve the problem once and for all, we advise
you to enter Islam, because Islam cancels out all previous sins and wrong deeds,
so save yourself from the Fire of Hell and earn happiness in this world and
the next. Once you have become Muslim there will be no element of doubt whatsoever
concerning the validity of your marriage, and the problem to which you refer
in your question will no longer be an issue at all. We ask Allaah to guide you
and us, and to give you help and success. Peace be upon those who follow true
guidance.