Answer and Explanation:
Dear Uncle.
I am inviting you to my paternal grandfather's 50th wedding anniversary. As you know, the whole family loves you and we would really like you to come and celebrate with us.
His presence is indispensable and we do not take no for an answer. In fact, Grandpa said he was looking forward to meeting you again.
The party will be held next week, on Saturday. The time is set for 6 pm, but I would like you to arrive early so that we can talk for a while.
Regards,
Your favorite niece, M.J.