İ know that it means good bye,but what is the exact translation for it

allahaısmarladık

ALLAH.... the name of ALLAH
ısmarla...from ısmarlamak .. to tell or order,to treat

Can we say it is a sentence

ALLAHa ısmaladık ... means to become treated by ALLAH , like in ALLAH care ?

I think in this case the meaning of "ısmarlamak" is "to entrust someone to" Allah.

Does ısmarlamak got the meaning of entrust too ?

yes,i found it

/ı, a/ to entrust (someone, something) to (someone).

Then it is more like a 'doa' prayer than a good bye

Like ,be in ALLAH trust

İ like it better then

But is it formal ,or informal,or can it be both ways ?

For example;
You came my home as a guest.When you decided to leave from home;
You should say 'Allahaısmarladık' or 'HoşÃ§akal'
And the owner of house should say 'gülegüle'

ohhh,but cann't the owner of the house answer Allahaısmarladık too ?

Well i like when i am the guest and i make a good prayer for someone, to make a nice prayer for me too, better than just good bye ,,lol

You'd better stay at home and wait for guests lol

yani,what will happen if i say Allahaısmarladık back ? lol

There wont be anything,nobody will kill you dont worry lol
I've just said its rule

weeelllll, you know what do they say about rules ?? lol