The truth is that whenever i eat an orange or a pear, i get very thirsty.
which word is the definite article?

The

Explanation:

In English, there are two types of articles: Indefinite and definite. The indefinite articles are "a" and "an" and are used for singular nouns. The definite article, on the other hand, is "the" and it is used for singular or plural nouns that are specific. So, in the sentence, the definite article is "the" and it is placed next to the noun "truth" to indicate that it is an specific or clearly identified truth.

my bad lil sis i promise tori