[susan53]

Sorry - I replied to this before but it doesn't seem to have posted ...

It's true that... is more emphatic than although and would be used to refute someone arguing the other case.... Because of the emphasis you'll often find it coupled with a word like nevertheless or still

A : She can't be that bad. Look at the results she got in the last exams.
B : Yes, well - it's true that the students all passed, but I still think she's a lousy teacher. If you ask me, her lessons were so incomprehensible that her students all did loads of work at home to make up.

A: You must have had a terrible holiday with all that bad weather. You really picked the wrong week to go camping.
B: Oh it wasn't that bad. It's true that it rained every day, but we had a good time nevertheless.