There is nothing wrong with your spelling.
Main Entry: her·o·ine
Pronunciation: \ˈher-ə-wən, ˈhir-, ˈhe-rə-\
Etymology: Latin heroina,
from Greek hērōinē,
feminine of hērōs
1 a :
a mythological or legendary woman having the qualities of a hero b :
a woman admired and emulated for her achievements and qualities
2 a :
the principal female character in a [COLOR=green! important][COLOR=green! important]literary[/COLOR][/COLOR]
or dramatic work b :
the central female figure in an event or period.
The drug is heroin.