Why was franz Ferdinand assasinated?
Presumably, this question is asking about Archduke Franz Ferdinand, heir to the throne of the Empire of Austria-Hungary, who was assassinated in 1914.
He was assassinated by a Serbian nationalist, Gavrilo Princip, who was essentially hoping to provoke strife in the Empire and enable the Serbs in the Empire to secede to Serbia. This is a simplification, and in any case the topic is debated. However, this is the essential element of the most widely held view of why Archduke Franz was assassinated. This assassination led directly to the beginning of the First World War.