If i work in a grocery store in the west alone as a cashier and a non mahram comes in alone to purchase, this is khalwa (seclusion) right? Do i have to tell her to leave? Or do i leave? Or should i avoid this job? This risk exists in working at stores in the west. What is your advice?

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 is His slave and Messenger.

It was reported in the Sunnah that it is prohibited for a woman to be in seclusion with a non-Mahram man. A warning against that is mentioned in the Hadith reported by Ahmad and At-Tirmidhi and narrated by ‘Umar that the Prophet said: “There is absolutely no man who stays in seclusion with a woman except that the devil is their third companion.”

Scholars have clarified the rules for the forbidden seclusion and that it is a man and a non-Mahram woman staying alone in a place where a third person cannot enter, so there will be suspicion, and one is not safe from temptation.

Based on that, your work in the grocery store is permissible even if a woman enters alone to buy from you because the grocery store is considered one of the public places people frequently visit in a way that a person can enter at any time, thus negating the forbidden seclusion.

Allah knows best.