From the experts:
Promise is one of those word names with an uplifting meaning that is making inroads as a girls' name, like sisters Dream and Serenity. How promising is Promise as a first name? Our try at cleverness illustrates perhaps the biggest problem with naming your baby girl Promise: It will be difficult for people to resist making bad puns on the name. We promise (argh) you'll be tired of hearing them well before your baby Promise's first birthday.