OK, this is a little complicated for my little brain but...
1. Svea is basically a word for the people who founded Sweden (Svea rike - country of the Svear - the people who lived in the area - sorry don't know the etymology of Svear). It is sort of used like
Marianne with
France except it sort of is the name of the actual country.
2. Svea is also used as a feminine form of the name
Sven which is dervied from the Old Norse name Sveinn meaning "boy".
I can find no evidence that Svea means "sweet one".
I hope this helps :)