Learn Dutch: Ik ben een jongen en u bent een man.

U is the formal word for "you" in Dutch. Because the speaker is a boy (een jongen) talking to an adult man (een man), he uses u to show respect.

Why is the verb bent used with u?

The formal pronoun u usually takes the exact same verb form as jij (the informal "you") in the present tense. For the irregular verb zijn (to be), that form is bent.

Why does the verb change from ben to bent in this sentence?

In Dutch, verbs change depending on who is doing the action. For ik (I), the form is ben. For u (formal you), the verb gets an extra -t at the end to become bent.

Does u need to be capitalized?

No, unlike the English word "I", Dutch pronouns like ik and u are only capitalized if they are the very first word of a sentence.