"The girl has bread."
Translation:Het meisje heeft brood.
Unfortunately this is something you have to memorize or learn through practice. As in French and many other languages, every word has a grammatical gender. And as in French there are some heuristics as to which gender a word has but no firm rules.
Masculine and feminine words use "de", neuter words use "het." Any Diminutive is always neuter, so "meisje" ("little girl", but often just "girl") as diminutive of "meid" ("girl" but used less often than "meisje") is neuter: "het meisje" whereas "meid" is feminine: "de meid."
Not to discourage you, but even native speakers sometimes get these wrong - mostly because some words have different genders in different dialects.
Just tried to pronounce "meisje" with Google Translate and it keeps hearing "mezen" ie. tits? Please tell me this is just a computer thing? Humans would hopefully understand? This would be a terribly embarrassing mistake to make in conversation. "Do you have a girl?" "Yes I have tits". Ack!
It depends on the word gender. "De" is used for feminine and masculine words, "het" is for neuter words. Some words can take both. And, important in the case of "meisje": all diminutives take "het": de tafel -> het tafeltje; de vrouw -> het vrouwtje. Unfortunately there are no rules that can tell you what the word gender of specific words is; you just have to learn them.
Meisje is technically a diminutive: it comes from "meid" + "-je", where "-je" is a suffix meaning "little". It's one of the few remaining suffixes in Dutch. "Meid" has the same origin as the English "maid" and just like in English can mean both girl/woman and (female) servant. So meisje means little girl.
Anyway all this to say that meisje is a diminutive and all diminutives in Dutch use "het", always.