interesting observation，永學哥！

I didn't realize "chr" combination is only pronounced as "kr", great observation!
But the point we are discussing is not to distinguish tr vs. chr. The title was using "chr" to refer to the sound [ch]. I think it boils down to how to pronounce "tr" cluster correctly so that it doesn't sounds like "ch" by itself, like dirtytalk said: if "ru" is not pronounced correctly, "true" can't be either.