All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
A person bears no sin if he denied someone something and then gave it to him later; rather, this is praiseworthy, especially if the giving involves what is good. Neither the giver nor the recipient bear a sin for this.
If the giver had taken an oath not to give the recipient and later gave it to him, then he has to offer an expiation for breaking his oath.
Allah knows best.