Most people pronounce the spanish Vicente as "Beethenteh" in castellano but you can definitely ignore the "th" sound and pronounce it like an S, it's your name after all, you make the rules! In some spanish languages there's no "th" sound (e.g. Catalan) so it's really not an issue.

It will definitely be much easier for spaniards to pronounce the english version of Vincent than the french. We probably have the worst french pronounciation in Europe despite the fact that we're neighbours! I always chuckle with how some people pronounce croissant: "curasan" (an attempt to transliterate as "cruasan", I believe).