http://list.indology.info/pipermail/indology_list.indology.info/2010-March/034209.html
I believe this is the best explanation (and where the conflicting meanings originates, as apparently there are people believing this is another name for the goddess Lakshmi (hence the meaning "god" that pops up occasionally)
Saisha
saiṣā
sā eṣā
sā = granting, giving, bestowing, she
eṣā = wish
So Saisha could possibly mean something like "she/grants a wish".
Not sure where the "meaningful life" meanings come from... possibly from an association with the goddess Lakshmi, or it's the meaning of a similarly sounding name? But seeing as the 'sa esa' explanation comes from a Professor of Sanskrit and Linguistics, I'm going to trust his judgement over that of random baby name websites lol.
My PNL = http://www.behindthename.com/pnl/37275
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