Questions & Answers about Onda ću doći.
Ću is the 1st person singular future auxiliary, from the verb hteti (to want), but here it functions like will in English.
So:
- ću = I will
- doći = come / arrive
Together, ću doći means I will come.
In Serbian, the subject pronoun is often left out because the verb already shows the person.
Here, ću already tells you the subject is I.
So:
- Ja ću doći. = I will come.
- Ću doći. would sound incomplete on its own
- Onda ću doći. is fine because ću already marks I
You can add ja for emphasis:
- Ja ću doći. = I will come.