Believe is used as a verb, and can be used as a transitive verb or an intransitive verb. The basic meaning is "believe", which means to believe the truth of things or believe what someone said.
1. Believe basically means "believe", which means to believe in the truth of things or the words of someone, which can be interpreted as "trust" or "belief".
2. In spoken English, "believe" can also be used as "think" or "think", which means a gentle and uncertain tone, equivalent to "make a promise". Sometimes, it just means polite, rather than being too absolute.
3. When "believe" is used as a transitive verb, it can be followed by a noun, pronoun or that/wh clause as the object, or it can be followed by that clause (indicating the future) as the double object of the direct object; It can also be followed by "(to be+) n./adj." or the infinitive of the verb as the compound object of the complement (indicating the past or the present). When used as a verb without something, it is often followed by the preposition in.
4. When believe is in the passive voice, the infinitive is used to follow.
You are believed to be honest.
5. Make believe is an idiom, meaning "pretend".
She made believe to be ill.
In the sentence "believe" is an infinitive, but because it is preceded by "make" without a specific object, "to" is omitted.