"She is an interesting woman."
Translation:È una donna interessante.
I'm not 100% sure about this so don't quote me but I'm guessing the verb is "interessare" = "to interest [someone]" therefore the past participle is "interessato" = "interested".
Unfortunately the English -ing ending can be misleading because it usually implies that you are currently doing something e.g. "walking" = "camminando", but on the whole in Italian you'd use the present participle instead e.g. "io cammino" = "I walk" / "I am walking".
"Interessante", meaning "interesting", is an adjective, not a gerund verb, so you probably just have to memorise it. If you actually wanted to use the gerund "interesting" e.g. "the lion was interesting the crowd" you could presumably say "interessando" although there would probably be another, better, way of conveying the message.
Disclaimer: it's half-past midnight and I'm using knowledge I learnt over a decade ago so please correct me if I've said something incorrect or nonsensical! :)
I am very confused with adjectives and when they do or don't change their ending in relation to the noun they are describing. I thought it would be ...una donna interessanta ... but no. Is it true that the adjectives ending in 'e' like interessante and grande don't change in relation to the gender of the noun they describe? Or, how is a person meant to know?
Good question! I wondered too, and found this: Adjectives ending in -e have only two endings for both masculine and feminine: singular -e and plural -i. Some color adjectives (rosa, blu) and foreign words are invariable. Examples (ragazzo= boy, alto= tall): masculine singular feminine singular masculine plural feminine plural un ragazzo alto una ragazza alta dei ragazzi alti delle ragazze alte un uomo intelligente una donna intelligente degli uomini intelligenti delle donne intelligenti http://www.italyheritage.com/learn-italian/course/grammar/adjectives.htm