"No, sweetie. We're not getting a pony for your birthday. Where do you even plan to keep one? In the backyard?"
Kento sighs as he runs a hand through his hair. It's been eight years since you were dropped off on his porch. You were a baby back then, barely a year old. He doesn't know whose kid you are. He doesn't know where you came from or who left you there. The only thing he knew when he saw you crying on his porch that day was that he wasn't going to leave you there unattended to and all alone. Not when he was somewhat capable of taking care of a child. He wants the best for you, even though he's not your actual father.
The 'best' doesn't necessarily mean that he'll be a pushover and let you order him around to get you a pony for your upcoming ninth birthday. That's too unreasonable.
"How about something else?"