* 시드니 (Sideni): This is the most direct transliteration of "Sydney" using Korean alphabet (Hangul). It's commonly used for place names, so it would be understood but might sound a bit foreign to Korean speakers.
* 시드니 (Sideni) + Surname: You could combine the transliteration with a Korean surname to create a more natural-sounding Korean name. For example, "김 시드니 (Kim Sideni)".
* Meaningful Translation: You could also choose a Korean name that has a similar meaning to "Sydney" or its origin. For example, "서울 (Seoul)" could be used as a substitute since both names refer to capital cities (Sydney is the capital of New South Wales, Australia).
Ultimately, the best translation would depend on your personal preference and the context in which you'd use it.