Maude is the village healer of Trebond, and she helped raise Alanna and Thom. They must've been a handful, because she can't wait to pass them off to someone else: "The woman had been looking forward to the day when someone else would have to handle these two" (1.25). (Based on what we know of the twins, we can't really blame her.)
We know that Maude's a decent healer, but that she doesn't have much else in the way of magical ability. When she attempts to ask the gods for guidance for Thom and Alanna's sake, she takes a big risk: "Maude wiped sweat from her face. She was afraid" (1.28). What she sees unsettles her, but she helps the twins go ahead with their plan anyway, so we know that Maude has guts.
Not only that, but Maude also helps Alanna win over Coram, filling Coram's wineskin with the lord's best brandy, and giving Alanna a hangover cure to help Coram the next day. Maude may not be the most powerful magic-user, but she cares for the twins, she's brave enough to give them a chance at fulfilling their dreams, and, let's face it, she's kind of the village healer/ witch you wish you had.