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.
We have already issued Fatwa 84351 about the excellence of forgiving, therefore, if you forgive your cousin, then this is very good, and you will, no doubt, find a blessed and good consequence of this, Allaah willing.
If he asks your hand for marriage, you should accept him especially since you mentioned that he is now steadfast on the straight path.
It is confirmed that the Prophet said: "If a man whose religion and moral conduct are pleasing to you asks to marry your daughter, you should marry her off to him." [At-Tirmithi].
Finally, the two following matters should be mentioned:
1- You should avoid suspicious places where one might be subjected to affliction, and you should be keen on wearing Hijab and abiding by the requirements which will help you preserve your dignity and chastity.
2- A cousin is a marriageable person to you, therefore, you are not permitted to talk to him or be in seclusion with him unless the religious requirements are met.
Allaah Knows best.