Ich nehme an, Du meintest Maria

here it comes:

"When you ask Trevor in the Merchants Guild about purchasing a house he will
say that only members are able to rent or buy a house AND you also need a
recommendation from someone who was born in Verdistis. To do this you first
need to expose Malcolm and join the Merchant’s Guild, and then you can tell
Trevor about Maria’s plight and he will agree to help restore her family’s
reputation.

Go back to Maria and tell her the good news, and she will immediately leave
for Verdistis. Go back to the Merchant’s Guild to find Maria inside, ask her
for a recommendation and she will gladly give you one. You can now talk to
Trevor who will allow you to rent or buy Malcolm’s old house.

You can rent the house for 1,000 gold pieces a month or buy it outright for
30,000 gold pieces. I think that renting the means that you will have to pay
Trevor 1,000 gold pieces every 30 days. Renting a house is a MUCH more cost
effective way of getting the house, as you would need to be renting the house
for like 900 game days before you reach the 30,000 gold pieces you would
spend by buying the house in the first place. Then again, you may just want
to buy it to avoid the hassle of remembering to pay the rent...

-Note: If you forget to pay the rent then Trevor will take back the house and
won’t allow you to rent (or buy) again."