Is there any way to politely ask an independent provider whether she tests regularly?  I don't want to come across as rude, but has anyone been successful asking?  I only meet higher end ladies (all independent), but it would still be nice to confirm that testing is done regularly.

Pull up your big boy panties and assume responsibility as an sexually active adult. Practice safer sex by using a condom for vaginal, anal AND oral. Most importantly, get YOURSELF tested first and foremost and test regularly.  

You ask her if she's been tested.  She says, "Yes, I get tested every month and I'm fine."  Do you believe her, or do you ask to see a copy of the test results?  How do you think that'll go over?  And even if she shows you the results, how do you know they haven't been faked?
IOW, it's a waste of time, won't tell you anything but will sure kill the mood quick.  Anyone who will work with an active STD will lie about it if she must.

I have been doing this for a long time as a provider and have never had anything. I still get tested on a regular basis just to make sure. I am sure there are providers out there who do not do this.  Use a condom. Every time.

They usually offer up when they were last tested.
Give something, get something. When two adults talk.

All you can do is protect yourself.  Condoms and regular testing. I know others have stated this but I can't even urge you enough to cover and test! ATLEAST every 3 months if you are an active hobbyist or provider.  
XOXO  
TL

There was a guy recently emailing providers and requesting appointment but also request to see std testing results, the result is-no ladies want to see him lol.even though he wasn't rude girls felt offended.

It's offensive that some clients think that I don't know how to take care of myself. And of course, the ones who ask this tend not to have been tested themselves.

if the provider is someone who doesn't test regularly, do you think she'd actually tell you? i mean think about it, if she's dumb or lazy enough not to get tested frequently, she's probably going to lie about it anyways. this questions  is ALWAYS irritating, often makes us think you want bbfs, and doesn't get you an answer you can even trust.

So she tests twice a month, for example
What about the guys she sees in between?
Or her bf? Often times he's not the most stable guy around.

Someplace where the awful experience of getting an STD test is turned around and you get unicorns and My Pretty Pony.  However, in that world, I’d probably blow my brains out before too long because there is too much glitter and emojis.

Explaining to the receptionist why I am there.
Avoiding the judemental stares in the waiting room.
The look on the doctors face, almost laughing, while asking me why I am so paranoid.
The nurse taking some extreme pleasure in sticking a needle in my arm trying to get back at an ex.
Asking to pay in full the day of the test, but still get a bill sent to my house.

Maybe hobbying isn't for you then...

The more I think about it, in the bizarro world where getting an STD test is the same a getting a happy sticker for giving blood, the closer I am to retirement.

So why even ask?

...  just assume she hasn’t and Protect YOuRsElf.