OK you got a hose connected to the pump. Congrats your half way there.
I dont know about silicone for this. you want to be able to take it apart and clean it when you need to right? It only needs to fit snug. Its not like a radiator hose or anything. Just do like I said and wrap something around the base of the pump fitting to make it larger like that plastic wrap. It will fit snug. You wont need the silicone. Then use your clamp if you want.
Now I am looking at your original pic of your PVC and I see a valve. The white thing with the red handle. There is a grey pipe sticking out of that. I assume that is the 1/2 you want to connect to. I also assume it does not screw in, it's a short piece of PVC cemented into the valve. So you need to change that to a threaded end and get a PVC 1/2" Starter Fitting that will attach to the 1/2" hose.
What I would do is get a 1/2" fitting with male threads cost like 50 cents and cement it to the end. Then get a double female fitting (threads on both ends) and attach that. Now what I had originally recommended you get will work. It is a 1/2 barbed to thread fitting.
Here, I will take a pic of an extra one I got.
screw that into the end of the double female fitting and the hose slides over the barbs holding it in place.
So you need the three fittings do do it this way. There may be an easer way but thats how I would do it.
Unless that valve is threaded then just attach it to that.