Trunks should however stronger Vegeta was from normal Earth-bound training. There shouldn't be a difference between the two of them. So that means that Trunks could potentially be equal to Majin Vegeta SSj2 or the version of Vegeta that returned from gravity training after the fight with Beerus, which could potentially make him stronger then Goku SSj3 (Boo), since Vegeta was able to grab the attention of Whis after returning. However, I'd place more merit on Trunks being equal to Majin Vegeta, maybe even only Vegeta SSj2 Pre-Majin...