Sarai signifies my lady, or my princess, which confines her dominion to one family; but Sarah signifies either a lady or princess, simply and absolutely without restriction, or the princess of a multitude, the Hebrew letter he being taken out of Hamon, and added to her name, as it was to Abram's name.
Related Commentaries of Genesis 17:15
Genesis 17:15
15 And God said unto Abraham, As for Sarai thy wife, thou shalt not call her name Sarai, but Sarahe shall her name be.