The first thing that you must consider while choosing a center stone for your diamond promise rings is the size of her hand. If she has small hands, for instance, then a solitaire set on a delicate band will look bigger on her finger. In fact, the larger diamond on the ring may overpower the overall appeal of her hand. Similarly, a smaller diamond promise ring will look even smaller on the hands of a woman who has bigger hands. Once you choose a carat size for your promise ring, analyze the diamond size charts in order to figure out the best shape and cut for that carat size. Then only, you will be able to make a ‘wow’ appeal with that diamond option. Besides, the carat weight of a diamond is directly proportional to its cost. Hence, you may consider a diamond ring cut that will give the appeal of a higher carat diamond in the case you are looking for an affordable purchase.