Classical Sanskrit "ah" Visarga sound is Vedic Sanskrit "as" (and Classical Sanskrit will accept "as", "o" sounds depending on Sandhi rules).
Greek will make it "os" and Latin will take this as it is based on Greek. Bengalis also tend to make "a" as "o".
"ram" - is the verb root to delight, make happy, enjoy carnally, to be glad or pleased, rejoice at, delight in, be fond of. "ram" will become "rom".
To make it Noun or Adjective through Active Present Participle, we would add "ant" suffix. So it becomes "rom ant".
To make it as "ness", one would add "ik" sound as suffix. So it becomes "rom - ant - ik" which becomes written romantic but pronounced as "romantic".
