is it safe to sale things on marketplace?

If you have to meet people in person to sell things, then obviously you should agree to meet ONLY in public places with a lot of people around. A cafe, or a crowded parking area, for example. Never ever meet someone in a place without a LOT of other people around.

I am unfamiliar with marketplace but have sold many things, including furniture and a stove, on Craigslist.

After posting and replying to many ads, I can usually get a "feel" for the buyer's intentions.

I sold some large items from my mother's condo after she passed, and several times I asked a neighbor to just come and "hang out" while the buyer was there.

For smaller items, I've met people in a shopping center parking lot, and once I met someone at the fire station in my neighborhood.