Hi everyone!
’To make a long story short’ means to tell someone something with few words.
You are providing just the basic facts instead of giving a long explanation.
【For example】
ex1.
Antonio: Hey, how was Italy?
John: It was a little crazy but to make a long story short, I had a good time.
ex2.
Leon: How are things going with your girlfriend?
John: Not good. To make a long story short, we broke up.
Leon: That’s too bad.
ex3.
Sally: Have you decided what business you’re going to start?
David: Yes, I’ve been thinking a lot lately, but to make a long story short, I’m going to open a gym.
●日本語解説：「簡単に言うと」という意味です。