To choose the correct shape of diamonds for the ring one should consider the following facts:

Learn about the 4 Cs of diamonds: cut, color, clarity and carat. Every diamond shape requires different quality concern.

Carefully look for the stone trends liked and worn by your fiancé. If she wears a princess cut stone ring or necklace then selecting a princess cut diamond engagement ring is appreciable and preferable.

Different diamond shapes have different costs associates. Round diamonds are comparatively cheaper than other cuts. So, first decide your budget before going ring shopping.

Look out for the shape of the fingers of your mate. If she is thin then an elongated diamond shape like oval is better. For thick fingers, round or peer shapes are better.

Compare the diamond shapes for the same quality and carat weight. Buy a ring that is certified and check about the exchange conditions so that if the ring does not suit the preferences of your bride-to-be, you can exchange it for another ring of her choice.