hatva -- having killed; kamsam -- Kamsa; ranga -- the arena; madhye -- within; pratipam -- the enemy; sarva-satvatam -- of all the Yadus; yat -- what; aha -- He spoke; vah -- to you; samagatya -- by coming back; krishnah -- Krishna; satyam -- true; karoti -- will make; tat -- that.

Having killed Kamsa, the enemy of all the Yadus, in the wrestling arena, Krishna will now surely fulfill His promise to you by coming back.