StOrY aBoUt My BeSt FrIenD

-Assumption:

This morning i received a call from my best friend named Hui Boon. When i answer her call, i heard that she is crying I'm so scared because i don't know what happen to her. After she calm down, she told me everything about her boy friend. She said, that suspect her boy friend (my friend too) outside got another girl friend she continuously crying but as my stand i can't say anything because both of them are my friends so i just listen to her. But in my mind i assume that this guy is very bad attitude and worse because he doesn't threat my best friend as well as i think.
I was so angry, then i called his boy friend and asked him what was happening actually. And he told me he doesn't do that but i asked him again why his girl friend will suspect him, is that any problem with you!! ..... After few hour, i received my best friend call again, she was so happy while talk to me because her boy friend already explain everything to her and this is only a misunderstanding.
My assumption is a set of belief which consider self-evident not further support analysis, people should be very carefull when making assumption because it's easy to make wrong assumption without evidence and so forth.