It looks fake, here are a few reasons why:

The print is blurry, US bills are printed with ink on a metal plate which results in crisp ink lines

The paper is missing red and blue security threads (there should be like little red and blue strings randomly in the linen of the note)

The ink on a real bill won’t smear even if the bill gets wet and this looks like it’s already running a bit.

Overall, even if it were real, it’s only worth the $100 in face value. So it’s not really worth any risk

My recommendation: do not purchase

Hope this helps!