Quite possibly the most frustrating NPC in the game. It is recommended to relay teleport her to outside of the square and kill her.

This NPC nearly drove me insane with her cycle of small-talk. That is, until I figured out that at the point X:337 Y:117, the point directly west of the statue where the grass intersects with the cobblestone... Ada makes a brief pause which allows you to trap her by surrounding her with barrels. From this point, everyone is too far away from her, so she stands there quietly.

Hi, here is what we did to box her in for a semi quiet Merchant square.

She did my head in so I hid my guy far away on the tower near entrance, then summoned a Incarnate to go kill her.

Yer safe among friends never forgetti

I 2k chest´ed her.

Why all the hate? This dwarf is hilarious hahaha

Protip: Have each of your characters talk with each of the Merchants at the square individually, and she'll just wander from booth to booth without talking to anyone, lol. You can still trade with your whole party, too.

talk to her with one character near the fire books seller, cast (with another character) telleportation on that character to place him on the shore with the boat and the corpse near the entrance.
Ada will follow the character that was talking to her... no one will hear her there.