Where is it safe to buy camera Nikon 810 with lense?

I would want to buy a camera that is unused but is an original product. The lense are 14/24 f 2.8

In the US some reputable vendors that are competitive in price include amazon.com, adorama.com, and bhphoto.com
There are others. If in doubt, do a lookup at bbb.org
If there's no listing, or if it is less than an A rating, avoid it. If the price is just so great you just can't resist it despite the absence of a BBB listing, then just try harder to resist it. You don't save money buying from a scammer.

If you don't have an abundance of money, don't get an FX camera. As you can see with that Nikkor 14-24mm f2.8 good FX lenses are expensive. That 14-24mm should work well for the situations where very wide angle is a good choice, which will be much fewer than ones where longer focal lengths work better.
Also, for those 36 megapixels to look sharp you need a good tripod.

Www.bhphotovideo.com 1-800-854-5575

www.adorama.com 1-800-223-2500

https://www.amazon.com/...amazon.com /

These 3 are good places to buy from.

You can buy it directly from Nikon, B&H or Adorama, or Amazon all good.