Hi Romek and welcome to the InfoPath Dev forums.
Unfortunatley rich text from InfoPath won't show as Rich Text in SharePoint, it is a limitation of SharePoint/InfoPath. There is also a limitation with the size of the column in SharePoint, by default the maximum amount of data from your InfoPath form is only 255 charachters. There is a hack (editing the manifest.xsf file) to get around this but it does not fix the issue with the bold, bulleted etc getting from InfoPath to SharePoint.
Ted