From my experience, both weapons do amazing damage on one, single target. Since I having a daring class and I'm focusing on a Str and Dex pure, which is the better weapon for single target damage?

I would say TS in my opinion even though it is never really a single target weapon every thing about it will always hit multiple targets and as far as dps goes it's better than sword, sword can pack a punch don't get me wrong but the speed of TS makes up for it plus the fact you will be pure dex so crits will help a lot, the only down side which the same rings true for sword also is you must be careful as you will have less hp compared to sword and no defence so you can't get hit.

Twin blades just becasuae of the dextirty you could always change to the bow.