If this connection is a simple hose to an un-threaded pipe with a hose clamp, it is important for the hose inside diameter to be the same as the pipe outside diameter. If this hose pipe is a good one, it should have several ribs on the pipe, which make it hard to put on the hose and gives the clamp something good to press the hose against.
Either of these or both is likely your problem. Generally speaking, with a good clamp and enough torque, you can stop a leak like this. One other thought, if that pipe is plastic and not brass, it could be cracked.
John & Clare Lyon
2007 43.5' Monaco Dynasty Palace III (All Electric)
Towd: 2011 Chevy Equinox