Lower level thief looking for a build/advice
For hearts/DE’s, I strongly prefer Sword/Pistol. You get an inherent AoE from your attacks, a stun, and good burst damage. I was (and still can) take on 2-3 mobs without an issue; more if I play it right and they’re melee.
Dungeons are a bit different, and will depend on your group make-up. Typically you’ll want to be running with traps, Shadow Refuge and/or Blinding Powder for your utilities. Lots of players like condition builds for dungeons as you can use the SB and stay at range whilst stacking bleeds/poison.
[TKG] Mollify