I bought this plant about a year ago at Marsh when it went out of business & it was labeled “Tropical plant #3”. I have spent hours on the internet to identify it & even contacted a local greenhouse but no luck. When I bought the plant it was about 8 inches tall and now it’s about 24 inches. It grows rapidly year round. During the warm months I move it outside because it seems to do better with bright/humid atmosphere. Now it sits on our North facing balcony and gets 3 hours of direct light (thank god im moving to a house with East and West facing windows!!). About 2-3 weeks ago it started to develop what appears to be berries? But they are only growing on one “stalk” ... I recently redid the soil because it was very packed down and the root system is composed of many small roots and zero large anchoring ones. They were also very shallow in the pot considering the plants size. The new leaves start red and turn a very deep green. I just want to know the best environment.
I think this is an Ardisia, which is classed as a tropical plant, and these 'berries' are in fact flowerbuds, which turn to red/black berries later on. Most likely Ardisia elliptica, images here https://keyserver.lucidcentral.org/weeds/data/media/Html/ardisia_elliptica.htm but could be a different variety.
This variety is unusual as a houseplant, Ardisia crenata is much more common, and I can't find any information in regard to keeping this particular one as an indoor plant, but probably it responds to similar conditions as advised in this link https://www.engledow.com/green-scene/2015/09/ardisia-plant-care-instructions-national-indoor-plant-week-2015/. Yours actually looks pretty healthy, so whatever you're doing already seems to work well.
Leaves look like Ixora. Perhaps I. odorata