Some jewelers will, some won't.
The value of a diamond depends on its cut, its clarity, its colour and its carat weight. A local jeweler can give you the answer you want.
take it to a jeweler
Best practices dictate that you take your diamond ring to the jeweler and ask the jeweler if s/he is interested in buying it.
You take your ring to a local jeweler and ask that the jeweler test the diamonds with a probe to confirm that they are, or are not, diamonds.
Take your diamond to a local jeweler whom you trust, and work with the jeweler to set the stone in the metal. The jeweler will charge you for workmanship and for raw materials required to accomplish the finished product that you commission.
Your local jeweler can show you a ring like this, and give you a price for the one you want.
Take your ring to a local jeweler who will explain that the 925 marking on metal always indicates something about the metal and never indicates anything about the jewel. As well, the jeweler can help you determine the reality of the gemstone set in the metal.
A 2 carat diamond cushion cut ring would make a beautiful engagement ring. The price of such a ring would vary from jeweler to jeweler; however, one could expect to pay from around $450 upwards.
It is safe if you are selling it to a jeweler of repute.
Diamonds are seldom permanently mounted, as this could damage their value. To change the diamond or the ring, go to any jeweler who makes custom-made jewelry.
Diamonds are set using a combination of glues and physical manipulation of the ring. A jeweler will bend the prongs of the ring to hold the stone.
My girlfriend's knees literally went weak when she first saw the jeweled tiara.