Question

Why do Julia and Winston feel safe meeting in the room above the antique shop?

Answer 1

Winston had earlier realized that the antique shop itself did not have a telescreen, hence it was unlikely that the ministries (the government) could spy upon them, or that the owners of the shop cooperated with the government.

Step-by-step explanation:
Edge 2022 (Took it from above to clarify that it's correct on edge!)

Answer 2

In the novel 1984, Winston and Julia feel safe meeting in the room above the antique shop because Winston had earlier realized that the antique shop itself did not have a telescreen, hence it was unlikely that the ministries (the government) could spy upon them, or that the owners of the shop cooperated with the government.