Learn Hardcore Indonesian: Ibu Dini datang tepat waktu.

datang: come (motion toward a place); neutral and common.
tiba: arrive (focus on the moment of arrival); a bit more formal.
sampai: arrive/reach; very common in speech, often with di (e.g., sampai di kantor ).
hadir: be present/attend an event; formal/official. All can pair with punctuality: tiba tepat waktu , sampai tepat waktu , hadir tepat waktu .

Ibu is a respectful title used before a woman’s name, roughly like Ms./Mrs./Ma’am. It can also mean “mother” as a common noun, but in this sentence it’s an honorific. The everyday shortened form is Bu. The male counterpart is Bapak/Pak (e.g., Pak Budi).

Why is Ibu capitalized?

It’s capitalized because it functions as a title before a name. Compare:

Title: Ibu Dini
Common noun: ibu saya (my mother), seorang ibu (a mother)

Can I say Bu Dini instead of Ibu Dini?

Yes. Bu Dini is very common in speech and informal writing. Ibu Dini sounds a bit more formal or careful, often used in writing or polite contexts.

Does using Ibu imply she’s married or a mother?

Not necessarily. Ibu is a general respectful title for adult women. Older Indonesian also had Nyonya (Ny.) for married women, but today Ibu is the default. For younger women you may hear Mbak in some regions.

Where is the past tense? How do we know when it happened?