Koreans use it when something catches their attention or curiosity.
Yes. "흥미로워요 (heungmirowoyo)" is polite and natural. You can also say "흥미로워 (heungmirowo)" casually.
You can say "That's very interesting" — 정말 흥미로워요 (jeongmal heungmirowoyo).
흥미로워요 means "That's interesting." 흥미 (heungmi) = interest/curiosity, 로워요 (rowoyo) = to be - polite. Common way to express curiosity when hearing stories, learning new facts, discussing topics.
1. Stories: New info, unusual story.
2. Learning: Class, discussion.
3. Social: Show engagement.
That's interesting. Tell me more.
That's really interesting!
Interesting. Really? (Casual)
Very interesting. (Formal)
• 신기해요 (singihaeyo) - Amazing / Fascinating
• 재미있어요 (jaemiisseoyo) - It's fun / interesting
• 대단해요 (daedanhaeyo) - It's amazing