The context of the following conversation is Jan tried to lie to Alex when asked, but alex knew Jan very well and knew better.:
Jan says I was trying so hard to spare Alex's feelings, but he knows me too well..
The friend responds That's the problem with good friends. So hard to deceive..
Jan responds Right, so I had no choice. I had to tell him what happened..
The friend responds So now he knows you saw his girlfriend with another man?.
Jan responds Yes, I don't think I've ever seen him quite so angry..
The friend responds I guess it's best that the truth came out. For Alex's sake..