If a Muslim woman committed a sin with a man, and on confession to her boyfriend expects he would no longer want to marry her, is it permissible to lie to him and say it was all untrue? She would like to marry him.
Initially you’d better notice that lying is considered as a haram act, then you should observe this matter. From the viewpoint of Islam, to save-facing (credit), we are not allow to express our committed sins, and solely ask Allah to forgive us (as @Ansari declared). Then you ought not to mention your bad past times. Of course it could be surveyed from another aspects such as:
According to Ayatullah Bahjat:
In case that being virginity has not mentioned as a condition during the Aqd (contract of the marriage) or the Aqd was not based on proving of this matter, it won’t be the cause of option (termination of the Aqd).
On the other hand, paying attention to the following issue could be beneficial for you that:
Lying in contracts among marriage is not permissible, but telling the truth is not Wajib and …
- firstly you ought not lie due to a love … (since in the mentioned issue, firstly you have committed a sin, secondly it will make some trouble in your future life that...)
- Secondly you’d better don’t mention the matter to him. Good luck.