Opinion evidence on relationships: conduct-based family or acquaintance opinions are relevant but not sufficient to prove marriage. Opinion evidence by persons having special means of knowledge, including conduct showing how parties are received or treated by friends or family, is a relevant fact when determining the relationship between persons, but such opinion is not sufficient alone to prove a marriage under the Divorce Act, 1869 or to establish matters in prosecutions under specified provisions of the Bharatiya Nyaya Sanhita, 2023.