Ysabeau Share definition Flag The girl's name Ysabeau \ys(a)-beau\ is a variant of Isabel (Hebrew), and the meaning of Ysabeau is "God's promise".Pronounced E'-sa-bo Ysabeau walks into a bar and all the other girls take a hit to their self-confidence. Ysabeau by A.L. Harper April 26, 2010 Get the Ysabeau mug.