A woman should be keen to choose a righteous husband who will fear Allaah with regard to her and will feed her and her children with halaal income and help them to avoid that which is haraam.
Hence we appreciate this question from you, as it indicates that you are concerned about this matter. We say: if the bank where this person works is a riba-based bank which markets and sells its apartments and buildings on the basis of riba, then it is not permissible to work there, or to help it with its projects in any way whatsoever.
Similarly, it is not permissible to work in building apartments or places for sin, such as leisure venues, places for gambling, riba based banks and the like.
It is on this basis that this suitor should be accepted or rejected. If his work is permissible and he is religiously committed and of good character, then accept him. But if his work is haraam or he is not religiously committed and of good character, then do not accept him, because marrying him will result in harm that will affect you and your children.
We ask Allaah for guidance.
And Allaah knows best.