The name Bettina is a girl's name of German origin meaning "God is my oath". Bettina and is often added to lists like Nicknames for Elizabeth and discussed in our forums with posts like "Girls Makeover - Two Middles".
From the experts:
Bettina is a dainty ballerina version of Betty, that has not been heard much since its 1950s-60s heyday. Bettina appeared in the Danielle Steele novel Loving, and in real life as one of Grace Kelly's bridesmaids.