How to best tell good tenant you want your property back

[Johnson Best]

A tenant who is paying on time without much problem except over a year ago her husband caused a big scene and now by law barred from my property.  

I need the property back for other purposes.  She knows the rental rules pretty well, and she is paying below market rental price.

How should I best inform her both humanly and legally and not missing any steps so she would have minimal confrontation from her?  

Thank you so much in advance.

[Nathan Gesner]

@Johnson Best you're probably over-thinking it.

Dear Tenant,

You are currently on a month-to-month lease agreement. According to California law, this lease can be terminated by either party by serving a written 30-day Notice to Terminate. Please accept this as your official notice. I expect the property to be vacant and the keys returned to me no later than (DATE) at 5:00PM.

I've appreciated having you as a tenant this past two years and wish you the best in your future endeavors.

The Landlord