My Husband bought me this tree 4 days ago. I think it's not healthy although it has great smell. Please, check my picture and help me to identify the disease and how to treat it. Thanks in advance.
That is a very unhappy Osmanthus fragrans, commonly called Tea Olive or Sweet Olive or Fragrant Olive. I'm afraid there's no way telling what the problem may be from the picture. I can only suspect that it has been ignored for many months at the nursery and is suffering the consequences.
This plant should be full, solidly evergreen in warmish climates. Container grown specimens should enjoy a fast draining potting medium and thorough watering when allowed to dry out somewhat. In very hot climates, they suffer and require protection from the hottest afternoon sun.
Return it now. Ask for refund or replacement with healthy one.