The phrase "going to" can have two very different meanings. It is very commonly used in english, so it is important to know the diffrences. For example:
1) 「Going to...」when we speak about something we have already decided. (話した前にもう決まったこと)
I am becoming really fat, so I am going to start my diet from now.
I have 1 week of vacation from my job, so I am going to take a trip to visit my friends in Japan.
I am really hungry, so I am going to buy a pizza.
2) 「Going to..」Guessing that something will happen (すぐに何か起こったことある)
It's really cold outside, so it is probably going to snow.
That girl looks much nicer than him, so probably she is going to reject him.
They are nice paretns, so I think their child is going to be nice too.
The other important phrase today is "Where are you headed?" You might hear this in english a lot. ^_^
1) Where are you headed?/ どこに行くの?
人A) I saw you riding your bicycle yesterday, where were you headed?
人B) Oh, I wasn't feeling good, so I was heading for the doctor's office.
Yes, "going to" can=will.
The small difference maybe is that "will" sounds a little stronger. If someone says "I am going to" probably they are going to do something. But if they say "will" the feeling is just a little stronger. I think both uses are pretty similar though.
Hi りっつる,
I think both are ok to use. They have equal levels of politeness.
You know, I am always happy to give some new expressions if that will help you. If there is a certain expression you need help with, you can ask me anytime. ^_^
Yes, that is right!
We can use "it's going to" when we are sure something is going to happen, or for a strong guess.
We can use it for things like weather, and also feelings.
For example, "He is on a diet, so if he eats that cake, he is going to get fat again"
Or
"I didn't study at all, so tomorrow's test is going to be really bad"
Thanks for your comments. I hope you write again! ^_^