Character by character
How it reads
This is a transliteration: the characters were chosen because they sound like Sandra. Chinese readers will hear your English name in it, which is the point — you will see this spelling in news, subtitles, and sports commentary. It is not a name a Chinese family would sit down and choose, and it does not carry a wish the way a native given name usually does.
The first character, 桑, is also a Chinese surname. That is common in these spellings and usually harmless, but it means the string can also be read as a surname plus a one-character given name — say the whole thing out loud in context before you use it on a document.
Using it as your name
Written this way, 桑德拉 works as a given name on its own, and you can add a surname in front of it. If you would rather have a name chosen for meaning — one that reads as Chinese rather than as an imported spelling — the Finder builds options from characters with documented meanings and shows you where each one comes from. Already using a Chinese name? Check it for tones, homophones, and famous-name collisions.
Source
ECDICT / common transliteration · Sandra
Spellings on this page are collected from published lists and from names real foreigners use in China. They are a reference, not a recommendation: a name you can explain is better than a name that merely matches a dictionary.