I was in a relationship with a woman for 3 years and during the Ramadhaan Allaah guided in Islam and I wanted to marry my girlfriend with Islamic rules, but we didn't find a solution and she left me, and according to my knowledge she is dating with someone else. My question is if she wants go get back to me should I accept and what should I do if I see that she loves me and she regrets for what she has done should I get back with her and marry her or what should I do if I verify that she treated me with someone else but she wants to get back with me.

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.

First of all, all perfect praise be to Allaah who guided you to Islam, and may Allaah make you firm and steadfast on this religion until the day you meet Him.

As regards you question, you should know that the most important thing a man should look into when willing to marry a woman is religion and a good moral conduct. It is confirmed that the Prophet said: "Choose the religious one." [Al-Bukhari and Muslim] This is because if the woman is religious, then it is more likely that she will fulfil the rights if her husband and raise his children according to a correct belief and good moral conducts.

If this woman you inquired about is a non-Muslim, and she is not from the people of the book, then you are not permitted to marry her as this is forbidden. Allaah Says (what means): {Likewise, hold not the disbelieving women as wives.}[Quran 60:10]. Even if she is from the people of the book, it is a condition for her to be chaste so that a Muslim may marry her, but if she is not chaste, it is forbidden for him to marry her. You mentioned that this woman has a boyfriend, so it is not permissible for you to marry her in this situation.

Moreover, marrying a woman from the people of the book has many disadvantages, so it is more appropriate for a Muslim to avoid marrying her in all cases. In this regard please refer to Fataawa 89418 and Fatwa 84724.

If this woman is a Muslim, and she is as you mentioned that she is has boyfriends, then it is forbidden for you to marry her until she repents to Allaah and becomes righteous.

Finally, it is more appropriate to forget about her and look for another pious and righteous woman; indeed there are so many women. Allaah Says (what means): {…and that you like a thing which is bad for you. Allaah knows but you do not know.}[Quran 2:216].

Allaah Knows best.