The emerald cut has one of the largest tables of all diamonds and was originally designed for the gem emerald. It is rectangular and has cropped corners. The inside of this stone looks like stairsteps. It is also called an antique cut, but not to be confused with the marquis. The asscher cut is very similar to the emerald cut, but is square. The princess cut is perfectly square and is very brilliant. Your round cut has the most sparkle and is thusly the most popular for diamond engagement rings. It has the most facets which is what makes the diamond truly shimmer in the light. The heart shape is shaped like a heart and is very sweet. A pear cut is shaped like a tear drop (or a pear) with one end coming to a point.
No matter which diamond cut she prefers, they will all be equally stunning on her hand. The best feeling of all will be knowing this engagement ring came from you and is a symbol of your commitment to marry her in the near future. She should not be as picky about the diamond engagement ring as she should about the man who gives it to her! This is a big deal so have fun and good luck!