Because Danielle is a French name, originally derived from Daniel, which means 'God is my judge' in Hebrew, it doesn't really mean anything, as such, in Japanese.
You can, however, still translate the name into Japanese, to be able to write and say it, using one of the three alphabets. Because it's a name foreign to Japan, you'd be recommended to use Katakana, which is reserved for foreign names and objects, such as McDonald's or television.
In Katakana, Danielle would be written like this: ダニエル, which roughly sounds like 'Da-ni-e-ru'.
Some people also try translate their name into Kanji, often because it looks more complex, and therefore somehow more authentic. Whilst you could choose characters to represent the name Danielle - either by meaning or by sound - it wouldn't really make sense to a native Japanese speaker. It would be much better to simply stick with Katakana, as it's the natural way to translate foreign names and words into the Japanese language.
