At first, Meryt doesn't seem like she'll play a very big role in the book. She's just the midwife who helps Dinah give birth to Re-mose—and Dinah's the one who tells her what to do. But Meryt ends up being Dinah's bestie, her best friend forever.
Meryt's the kind of friend who goes around telling everyone about how great you are; she's the true wing-woman of the Bronze Age. When Benia finds Dinah, in fact, he references Meryt, saying this: "I am lucky that your friend does not understand the meaning of 'no'" (3.3.103).
So Meryt looks out for Dinah's love life. But she also makes sure Dinah is held in great esteem by her family and friends: "Menna will tell you that she is a friendless midwife he has taken in out of compassion. But I tell you that I am her friend and her sister, and that I am her student, for I have never seen nor heard tell of a more skilled midwife" (3.3.44).
These kinds of friends can sometimes be obnoxious and make you turn red everywhere you go. But overall, they're the best kind of friend to have. They're the ones who'll always support you and stick by you wherever you go. Sure, Meryt might have a big mouth, but she uses it for Dinah's benefit. What's not to love?
Even when Dinah explains her true past to Meryt, there's no awkwardness or anger on Meryt's part. Instead, Meryt responds: "For all these years, no daughter could have made me happier or more proud than you. Now that I know who you are and what life has cost you, I am in awe that I number you among my beloved" (3.5.11).
Ah, the BFF. The BFFL. The Biffle. The Bestie. Meryt's simply the best of best friends.