Mandarin:
* Simplified: 温迪 (Wēndí) - This is the most common way to romanize the name.
* Traditional: 温蒂 (Wēndì)
Cantonese:
* Jyutping: wan4 di1
Other considerations:
* Pronunciation: The "W" in "Wendy" is pronounced similarly to the English "W". The "en" sound is similar to the "in" in "win".
* Context: You might want to consider the context when choosing the best way to say "Wendy". For example, you might use the more formal pinyin romanization when writing a formal document.
Remember that Chinese names are often translated to sound similar to the original name in the target language, rather than being a direct translation of the meaning.