prośba o sprawdzenie kilku zdań :)

I'm looking for a flat in the city center. Therem must be cheap grocery nearby and parking facilities. I need a fully furnished flat with nice kitchen and comfortable bedroom. I don't want to live alone. I have got a fiance and we're putting money away for our dream wedding so we need to find cheap apartment to rent.

brakuje czterech przedimkow
w fiance nad e jest akcent

no i co to za slowo therem :-)

I don't want to live alone. ja bym ujął np 'I'm not going to live alone.'

There must be (x) cheap grocery (ale co? tutaj brakuje slowa) nearby and parking facilities. I need a fully furnished flat with (x) nice kitchen and (x) comfortable bedroom.
I have got a fiance (reszta slowa) and we're putting money away for our dream wedding (tutaj dalabym przecinek) so we need to find (x) cheap apartment to rent.

ale jakos te 'there must' w ogloszeniu to nie za bardzo pasuje
raczej, ujmij to jakos tak:
It'd be great/fantastic if there was a grocery and some parking facilities nearby.

nie wiem, czy to jest ogloszenie, bo o dream wedding w ogloszeniach tez sie nie pisze

mg, to od ciebie zalezy, co w ogloszeniu chcesz zamiesci; tutaj jak widac ktos za bardzo chce pisac w dosc nietypowy sposob, moze to jest jakis sposob

... there was a grocery (ale tutaj brakuje albo 'shop' albo 'store' albo po prostu 'grocers') and some ...

mozna dac te shop albo store, ale samo grocery przynajmniej w AmE funkcjonuje