I'll go through sentence by sentence and point out your mistakes and how to correct them

"I had a plate of pieces of cutting of Mango at some store in Kaohsiung, Taiwan.

The English word for cut pieces is "slice", mango should not be capitalized and replace "some" with "a". Corrected sentence: "I had a plate of sliced mango at a store in Kaohsiung, Taiwan."

"I forgot where it was located."

The sentence is past tense so "forgot" should be "forget" but the store still probably exists in the present so "was" should be "is". Corrected sentence: "I forget where it is located."

"The store served a variety of cutting of fruits and a variety of flavors of shaved ice."

Once again we must use the word "slice". Also, sing "variety" twice is redundant. Corrected sentence: "The store served a variety of sliced fruits and flavors of shaved ice."

The word "Surely" doesn't really make sense here. You have stated that the store sells both fruit and shaved ice and therefore you need to clarify what you bought instead of saying "one". In English, a person doesn't sit "on the outside" of a table, we simply sit "at" a table. Corrected sentence: "I had a mango for $4 and sat down at the table."

"A woman cut for easy to eat for me."

Once again you must use the word "slice". Corrected sentence: "A woman sliced it to make it easier for me to eat."
"I’ve never had these cutting of the fruits at the store in Japan."

Corrected sentence: "I've never had sliced fruit at a store in Japan."

"It was so impressive and fresh."

This is a good sentence.

"My best favorite fruits is Mango."

"Favorite" and "best" are redundant. "Fruits" should be singular. Don't capitalize mango. Corrected sentence: "My favorite fruit is a mango."

"I like Mango snacks and Mango flavors of foods as well."

This sentence is good just don't capitalize mango. Corrected sentence: "I like mango snacks and mango flavors of foods as well."

"Do you like mangoes? How often do you eat them?"