How to write a letter to a teacher?

[Warvy]

++Please you (guys) mind checking my grammar.++

Dear Mr. Joseph

I'm truly sorry for not attending the classes this week. It is because I had to go back homeland for joining my close cousin wedding ceremony, because I was a bridesmaid. I had to help the wedding ceremony of my cousin. It took many days to become the completed beautiful wedding ceremony. Thus I did not go to school.
This is a demonstration for my absence. I hope you will forgive my absence on this occasion.

Yours Sincerely

M.Y.

[emsr2d2]

++Please you (guys) mind checking my grammar.++

Dear Mr. Joseph

I'm truly sorry for not attending the classes this week. It is because I had to go back homeland for joining my close cousin wedding ceremony, because I was a bridesmaid. I had to help the wedding ceremony of my cousin. It took many days to become the completed beautiful wedding ceremony. Thus I did not go to school.
This is a demonstration for my absence. I hope you will forgive my absence on this occasion.

Yours Sincerely

M.Y.

Dear Mr Joseph

I would like to apologise for not attending classes this week (do you mean "last week"?) I was a bridesmaid at my cousin's wedding in [name of country] and I needed to be there for several days before the ceremony to help with the arrangements.

I hope you will forgive my absence.

Yours sincerely

[Warvy]

Thank you so much for your help.