Complex sentence: The spouse of a jonkheer is not named Jonkvrouw but is named "Mevrouw", translated into English as "Madam", and abbreviated as "Mrs." (with the use of her husband's name).
Split into simpler sentences: The spouse of a jonkheer is not named Jonkvrouw but "Mevrouw". Translated into English this means "Madam", abbreviated as "Mrs." (with the use of her husband's name).