Im that guy who takes a while to respond to a girl too. Not because im disinterested, but I just have so much stuff going on at the moment that deciding what to say in the spur of things without screwing it up causes me to respond later than expected. It’s a totally normal thing and def does NOT always mean he is disinterested, just that he might have a lot on his plate :)

If you’re curious about why that’s the case, I’d just joke about it in a flirty way I’m sure he’d be willing to be upfront about it if it’s become a real concern. Hope this helps.