Original Korean: 왕난이 베슬 가나요.
The '왕난이' is just Wangnan with a particle denoting that he is the subject of this sentence.
The '가나요' means 'is/are [Subject] going?'.
The '베슬' is the tricky one, as it is not a korean word in itself, but an English word written in hangul. The words it can be is Vessel or Vassal. Given the context of the chapter it is most likely vassal, as Wangnan is trying to get Viole to do his bidding.
The meaning of the sentence is more easily seen when the '베슬' (Vassal) is replaced with the korean word '가신' and its appropriate particle.
This all leads to the meaning of the sentence being 'Is Wangnan's vassal going?'.