Sometimes it's difficult to digest bitterness but the end result of that bitterness is always good because it helps you to improve. The bitter truth sounds very harsh and may not like it in the first place but the lesson learned from that is sweet enough that we never repeat the same mistake.
I remember the instance when a friend of mine was lying to his wife about losses he made from gambling, later one day she came to know about this, and at that point, he had to say the bitter truth and he had a quarrel, it was very disturbing but it once for all.
He learned from his mistake and then he always told truth irrespective of how bad it was but better to learn from that mistake and it is a sweet moment to such bitterness.