All you have to do is beat his dad once you have 4 badges then walk to the next house get surf go to the place where there is water then click it and say yes
On route 119.
Use your pokenav to find it.
Regice: Route 105 Regirock: Route 111 Registeel: Route 119
you can get feebas on route 119 very rare
you can get it by going to route 119 at the tall grass
you can find a feebas in route 118 and 119 but its hard to find
Fortress city and go through route 119
Only in ruby, sapphire and emerald at route 119
In Pokèmon Sapphire, Rare Candies can be found on these routes: Route 106 Route 110 Route 114 Route 119 Route 120 Route 123 and 132. *One of them can also be found in the Trick house ~Lucario
in route 119
I'm not sure if it's the same on Sapphire, but it's on Route 119 right before you get to Fortree City (im playing sapphire, so it might be different)
Face and defeat your rival in route 119