This is a Rex Begonia which majors on the Red Shades.
I had hard times with them before as they are not hardy and these tones eventually vanish when planted in shaded areas.
However, I'm up for the challenge to try out again for the second time and confident that I will get through this time around.
I had hard time finding out the ID of this Begonia as it had similar names:
Begonia 'Stained Glass' & Begonia 'Beau Rouge'
There are a few more but I had not put them here, somehow the red sheen are more brilliant and brighter. As for now, I will content with this name & plant.
The underside is similar like a Rex Begonia.
Begonia Common Names and Images
Here is the link where I had put together a list of all the begonias that I had come across. A database of all the different types & their characteristics. Please click on the link on the title above for the post.