Learn German: Die Hälfte liebt den Snack, aber ein Drittel findet den Geschmack zu salzig. - Half love the snack, but a third find the taste too salty.

In German, fractions used as independent entities (like "a third" or "the half") are nouns and must be capitalized. With the exception of die Hälfte (the half), these fractional nouns are neuter and end in -tel or -stel, like das Drittel (the third) or das Viertel (the quarter).

Could I use the word halb instead of Hälfte here?

No, because halb is an adjective used to describe another noun, like ein halber Apfel (half an apple). When you want to say "the half" as a standalone group or portion, you must use the noun die Hälfte.

In English the translation says "Half love", but the German verb liebt is singular. Why?

In German, fractional nouns like die Hälfte and ein Drittel are grammatically singular. Even though they refer to a large group of people in meaning, the verb strictly follows the singular grammar of the noun. This is why the sentence uses the singular verbs liebt and findet.

How exactly is a word like Drittel formed from the number three (drei)?