My Father-In-Law wants me to write an essay on why I want to Marry his daughter

Help! I'm confused. I visited my soon-to-be father-in-law to ask for his daughter's hand in marriage and I got a shocking response. Rather than giving me his blessing, he asked me to write an essay about myself and
why I intend to marry his daughter. I don't get it? where is that done and why do I have to write an essay instead of him just giving me a chance to give my reasons? What should I do? Should I just go ahead and write the essay or not?
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