The suppositive verb ending -지요 (-jiyo) works best when asking questions. It is commonly added in a yes-or-no type of question to add an effect like isn’t that right? or isn’t that so? see examples below:
- 꽃을 좋아하시지요? (Kkoteul choahashijinayo?) You like flowers, don’t you?
- 갔지요? (Katjinayo?) He’s gone, hasn’t he?
with out 지, the question on first bullet is still okay but it would be simply asking — Do you like flowers? So 지요 instead of usual 요 ending adds the meaning that you have the impression he/she likes flower. This goes the same for the second one, using 지요 would make it sound as if you are guessing he already left.
In a question-word questions, using 지요 carries the tone ‘I wonder’ in English or what/where/why did you say it was?
So for the simple question ‘how much is that?’ — 그것은 얼마예요? (Kukoseun eolmayeyo?) When you use 지요 — 그것은 얼마지요? (Kukoseun eolmajiyo?) The question becomes ‘I wonder how much is that?’ or ‘How much did you say is that?’.