My mother has this plant on her window sill and we don't know what species it is. All I know is that it resisted temperatures below 0°C this winter. Any idea? I can take other pictures if necessary.
It looks like Griselinia littoralis "Variegata". It's an evergreen shrub native to New Zealand. Because of its dense growth, it is used widely in Britain and Ireland as a privacy hedge.
Identifying characteristics are the alternate, ovate leaves with the smooth cream colored margins. The interior of the leaves are yellow-green to mid-green, sometimes with more variegation.
If left to grow, it can become an extremely large shrub, but responds well to being trimmed back regularly. It will definitely outgrow the container that you currently have it in.