There is a difference between *mated* and *paired* .... many clown fish will *pair* and never have any babies together ... just a male and female buddies. A mated pair will lay eggs. Mine just laid eggs several days ago ... they can now be considered *mated*. It took mine ... almost 3 years.
If you are into the clownfish specifically for breeding ... it may be a while or possibly never with the two you currently have. ... They WILL establish their sex. That doesn't mean they will mate. .....or find someone selling *mated* pairs and ask for picture proof. Too many people sell paired fish as mated. It may be they just don't know or they could be deliberately deceptive.
User: KCaquatics may have more information on this for you ... as well, there are others successfully breeding clownfish in this club.