All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
If a woman pretends that she is not married and it is not known that she is married, and there are no disputes on this issue, then there is no harm in marrying her and believing what she claims, as in principle [one should believe that] she is not married. However, if one doubts about her, then it is more appropriate to investigate the matter. Finally, it should be noted that marriage is void without the presence and consent of her guardian.
Allaah Knows best.