If I am not sure whether a female will use lingerie in good way or bad way, then can I sell? After selling if it is used in bad way will I be sinful?
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The basic principle is that it is permissible to sell these clothes, and the mere possibility that someone might use them in a sinful way – as is the case with Tabarruj (unlawful exposure of beauty) – does not entail the prohibition of selling them. What is prohibited is to sell them to someone when it is known or believed that the buyer would most likely use them in a sinful way, or if such clothes are mostly used by women in a sinful way. Ibn Taymiyyah, may Allaah have mercy upon him, said: “It is impermissible to sell or sew all types of clothing that are most likely used to help commit a sin to someone who will use them for committing sin and injustice.” [End of quote, Sharh Al-‘Umdah]
You bear no sin if a woman uses these clothes in a forbidden manner and you did not know or mostly believe that she would use them for a sinful purpose when selling them to her.
Allah Knows best.