This is the 2666th most frequent Turkish word.
yapacağını
"Yapacağını" means "what you will do" or "what he/she/it will do," depending on context.
The word 'yapacağını' is used to convey a third-person singular future action, indicating 'he/she' will be doing something (in this case, the homework).
Bugün ödevini yapacağını söyledi.
He/She said (that) he/she would do the homework today.
'Yapacağını' here is employed to denote a future action promise made by the subject, Ali, pertaining to completing a task.
Ali, bu işi zamanında yapacağını taahhüt etti.
Ali promised that he would complete this task on time.
In this sentence, 'yapacağını' refers to a conditional or potential future action about which the subject's thoughts or beliefs are being discussed.