If you want to state your opinion and then encourage someone to agree, use deshou.
firipin wa atsui deshou?
The Philippines is hot, isn't it?
[You are expecting a 'yes' answer]
It hurts, doesn't it?
[You see someone who has just slammed their head in the low doorway]
But usually でしょう is used to mean 'probably':
Ame ga furu deshou ne.
It will probably rain, don't you think?
And another common usage is どうでしょう meaning 'how about...' or 'what do you think about'