Your right click attack is your strongest weapon against her, making Maeve unable to move fast for a few (valuable) seconds

Using Deep Roots Legendary card can cripple Maeve and once immobile her low health pool makes her an easy kill.

Use your root in case you picked the corresponding legendary card!

Artful Dodgers legendary or Resilence is a must, even when Grover doesn't use Crippling Roots as his legendary. You have two movement abilities and you're shut down if you can't use them.

Grover high HP and passive healing made it hard for Maeve to kill him effectively, Leaving Grover with more time to group up and gain reinforcement.