Yes, I agree with robynanne. We need to see pictures!
Please would you fill in your personal profile so that your location (city/country) will appear in your posts. This will make it a lot easier for your gardening friends here to help you out. Just a zone designation isn't enough, it only tells us how cold it will be in your average winter. We need to know what your climate and weather conditions are year round.
On this Star Jasmine plant, did you break up or loosen the root ball before you put it in the ground? Did you amend the soil around it with any goodies? Like, compost or peat moss or cow manure or ??
How much would you estimate you are watering the area? Are you sure you're watering the whole root area, because if the vine has grown any roots at all you need to water out from the base of the plant a couple of feet around it. I would first try soaking it really well, in a large circle around the plant. I mean literally letting the hose run on the root area for 10 minutes then move it to the other side of the plant and let it run again. Just a spray with a hose, or a short run with a sprinkler sometimes only wets the top inch or two of the soil, not down to the roots of the plant.
If it doesn't perk up after doing this, try letting it dry out for several days but it really sounds to me like it needs more and deeper water not less.
