Ferminized Seed question?

Ive i got ferminized seeds are they all gonna grow in to females and how do they make the seeds ferminized

The likelihood of them being female is VERY good, however, you can still get the occasional male. They are produced by taking pollen from male flowers that appear on a female plant LOOONG after she should have been harvested, and use to pollinate a female plant. The outcome is a 'female seed'.