I need a school certificate in a form of paper,
which proves that I have graduated grade 10 from this particular school.
I need this sort of certificate but the school said that they can provide the
one that is like a report card.
But what I need is a 'certificate' which has mentioned just the fact that
I have been in the school, and have graduated grade 10 in this particular school.
Teacher said that I have to write a request letter to get it,
and if I do, school will consider providing it.
I have my friend's which is similar to the format of what I want,
so I'll just copy the general format of how it is written below.

"This is to certify that the above-mentioned person successfully graduated class 10 in
this particular school from 2012..."

If there is any Grammar mistake in above sentence, please amend it for me.
And now, I have to write a letter that I want my certificate to start with the sentence
like this... And... I have no idea...
Could you please help me out?
Do I start with 'Respected Sir...' ?