Green, heart-shaped leaves, grows upwards on strong stalks/stems.
It looks like Peperomia, and judging from the shape of the leaves I would say a raindrop Peperomia (P. polybotrya).
The Peperomia likes bright but indirect light, and warm temperatures. I have one on a north-east facing window, so it gets only a little bit of direct sunlight very early in the morning in summertime.
Watering: let the soil dry up completely before watering. Don't treat it as a swamp plant, the roots will rot when soil stays wet all the time.