What is the ruling on sitting with a girl in a public place and conversing with her via WhatsApp, with the permission of her brother, for the purpose of getting to know each other with the intention of marriage, in a country where there is no other way to get to know Muslim girls?

It is preferable to speak with the fiancée in the presence of her guardian (wali) or a male mahram relative. It is permissible to meet in public places without seclusion (khalwa) or suspicion, if there is a need, and it is permissible to speak with her through communication applications, provided that the Islamic regulations are observed.