Learn Croatian: To je zaista dobra ideja. - That is indeed a good idea.

When saying 'That is...' to point out or introduce something, Croatian always uses the default neuter pronoun to (or ovo / ono), regardless of the noun's gender. You would only use the feminine ta if the word 'that' was attached directly to the noun, as in ta ideja je dobra (that idea is good).

Can I use stvarno instead of zaista here?

Yes, you can. Zaista, stvarno, and doista are synonymous adverbs meaning 'really,' 'truly,' or 'indeed.' Stvarno is the most common in casual, everyday speech, while zaista sounds just a little bit more polished or slightly formal.

Could the word order be To zaista je dobra ideja?

No, that would sound unnatural. The verb je is an enclitic (an unstressed word) and follows the 'second position' rule in Croatian grammar. It needs to come right after the first word or phrase, which in this case is To.

In conversation, is it natural to drop To je and just say Zaista dobra ideja?

Absolutely! Just like in English where you can simply say 'Really good idea,' conversational Croatian frequently drops the subject and the verb biti (to be) for quick responses and agreements.