Well, the good news is that link appears to be (can never be 100% certain) the actual WuXing company itself, rather than some 3rd party, so it's likely you would get the real thing from them. It's nice when an AB seller sets items up that way, but it's pretty rare in the stuff I've looked at so far.
Note that the ad specs include stuff like
Drop out
175mm or 145mm
Display
SW102
Wheel size
26 Inch
Brake lever
156PYD
but there aren't any options to pick which dropout width you'd get (the real term is O.L.D.), as they just have the one item listed. It appears to just be a bare motor, and this
Single package size:
17.5X12X12 cm
is small so I don't think it will include a 26" rim (or spokes), or the brake lever or display that it states it has.
Those are probably just incorrect listing info, but since they are wrong, *anything* on the page could be wrong, including the item description, pictures, etc--you could end up just getting a photo of a bare motor (doubt that would happen, but...).
Weight
4.5
but no units. Presumably kg, but the shipping says
Single gross weight:
4.000 kg
which means that one of those (or both) must be wrong. It would be *heavier* for shipping, not lighter, because of packaging.
The title itself says 500w and 750w, but there are not multiple motor options, so one of those is wrong, too. (sure, most power ratings are made up, but...there are already multiple mistakes on the page, and options shown that you can't choose, etc).
Regarding the "guarantee"...I wouldn't hold my breath about any of those for someplace I can't walk into and talk to a human about.

(and most of those, either).
Regarding the "too small an order", remember that Alibaba is the large-order company-to-company sales site, and Aliexpress is the sister site for individual sales of items. Many (but not all) Alibaba-hosted companies also sell on AE, as long as you can actually find their store (which may not be named anything like what the Alibaba store is).
For those that don't, you usually have to use google/etc to search AE for the product you're looking for, since AE's search basically doesn't work (you may get some results, but you won't get them all, and you won't get the best closest match for what you're after, most of the time).
I recommend a reverse image search to find AE pages with the same image as the AB site of the product you want, and if that doesn't work then try searching for the images on the AB site of the specs or some other image specific to that product pate. If that doesn't work you're stuck with text searches, and whether that finds anything depends on how they misspelled it vs the original and/or your search terms, and how good a day everybody's AIs are having when you try.
Wuxing 48v 500W 750W MTB electric bicycle motor brushless hub gear motor
Key attributes
Industry-specific attributes
Brand Name
Wuxing
Other attributes
Place of Origin
Zhejiang, China
Model Number
HM5001
Power
500W
Weight
4.5
RPM
400
Drop out
175mm or 145mm
Display
SW102
Wheel size
26 Inch
Brake lever
156PYD
Packaging and delivery
Selling Units:
Single item
Single package size:
17.5X12X12 cm
Single gross weight:
4.000 kg
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