I think couplea few things contribute to this destination.

First, I've watched quite a lot of anime.

Having "quite" when you have "a lot of" feels redundant. You can say "quite a few" or "a lot." Choose one.

But it isn't so that I just want to visit Japan because this country was origin of animeI want to visit Japan not only because it is where anime originated from.

The first part of the sentence feels clunky. Consider rewriting for clarity.

Anime rather showed different places in Japan and their culture(actually) showed me Japanese culture and many different places.

The word "rather" doesn't seem to fit here. "Actually" may have been the word you were looking for.

Also, I think it feels more appropriate for this sentence to come before the previous sentence. Reconsider your writing structure.

I know itJapan must be very different in real live fromity compared to what I imagine.

What is "it?" It's unclear. Is it Japan? Is it the Japan that anime showed you?

Also, "to live" is a verb. "Life" is the noun form.

But it's just a dream.

...?

I couldn't understand what you were trying to say with this sentence.

What do you mean by "it?" Make it clear.

OK?

?

:) ¶
Second, it's just feels so muchI get the feeling that Japan is very different from all other places to which I've been to.

When you use the present tense with "feels," it sounds like you're in Japan right now. Reconsider writing in the subjunctive mood.

And I'd like to have a new, unique experience.

The word "And" doesn't fit here.

I think a couple things contribute to this destination.

But it isn't sonly that I just want to visit Japan because this country was origin of anime.

I know it must be very different in real livfe from what I imagine.

:) ¶
Secondly, it's just feels so much different from all the places to which I've been.

I think couple things contribute to this destination.

another way you could phrase this sentence.
A couple of factors that contributed to my decision are as follows.

Firstly, I've watched quite a lot of anime.

But it isn't so that I just want to visit Japan because this country was origin of anime.

The fact that Japan is the origin of anime is not really the reason but

Anime rather showed different places in Japan and their culture.

rather the different places and Japanese culture showed in the anime.

I know it must be very different in real live from what I imagine.

I know, reality is very different from my imagination.

:) ¶
Secondly, it's just feels so much different from all places to which I'I have been to.

Andso I'd like to have a new, unique experience.

I think a couple things contribute to this destination.

But it isn't so that I just want to visit Japan just because this country was origin of animanime originated from there.

Anime rather showed differentRather, anime showed various places in Japan and aspects of their culture.

I know it must be very different in real live from what I imagine in real life.

:) ¶
Second, it's just feels so much different from all the places to which I've been.