Help with written notice for tenant to leave

[Vinh Nguyen]

Hi all, 

Today, I finally closed on my first flip through a wholesaler. He recommended me to give the tenant a written notice stating she has 30 days to vacate the property. I intend on flipping the property. As a motivator, I would include that I would return her security deposit that was given to me by the seller. 

I am not sure how to go about writing this letter without coming off as intrusive. 

Please advise.