Essentially, if it's not in premium condition, they can warrant a service call and the associated fees.Be careful when you confront them on it because you need to consider their defense.

People get real weird and confrontational when they're selling their homes because they've got their life wrapped up in that house and its hard to separate all that emotion. 

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?  

About a month ago she confronts me with "information" she could have only known if she had gone through my personal belongings.

Raising the rent too high could lead to undesired confrontation and may be difficult to find tenants moving forward if the current tenants choose to find housing elsewhere.

I would directly confront that tenant tell him that is absolutely inexcusable behavior-- if he is month-to-month, I'd 30 day notice him, if is lease is not close to the end, I'd 3 day him and tell him he has 30 days to move and if he wants to fight, his creepy comments can be part of a public court record.

He's been in the game for a minute but doesn't strike me as the confrontational type, so I guess he figured we'd work it out amicably later. 

Also, without being confrontational, bring up their exit in conversation.

On one hand you're getting your money, on the other hand it is late and every contact is confrontational.

There's nothing wrong with telling your tenants to leave by 6pm on a particular day but if they don't, you shouldn't confront them or try to push the issue.