On Sat, 5 Nov 2016 07:39:22 -0700 (PDT),
wrote:

Hey, I'm a Canadian, we don't abuse each other for making a typing error. I got my measuring tape out and the deck is 10 ft 3 inches wide and 14 ft 5 inches long.

One side (the side where the hot tub will be) is attached to the outside wall of the house.

The joists underneath are 21 inches apart. The other side is secured by 3 4x4 posts evenly spaced. Their website says it weighs 1972 lbs.

Without any more details, decks are generally engineered for 40 pounds
per sqft. Your tub is easily twice that. If you just put 2 4x4s and a
short beam under the tub it would be plenty strong enough, IMHO but I
have not proved it on paper.