Eg : As a "completing comment" when you're fed up with the discussion and want to move on without fully agreeing or disagreeing with the other point of view. Eg a head teacher and assistant head teacher are discussing another teacher's performance. The HT has been arguing that it's weak while the AHT has been puting forward positive points. the HT wants to close the discussion and move on :
HT : Yes, well, I suppose it's true that she gets good results. Now - what about Adam Johnson?
If you want other examples, feed it into a concordancer . Try
Lextutor. Type "it's true that" into the "Keyword box, and then select "All of the above" from the "Choose a corpus" box. Then click on "Get concordance"