Kimse elindekinin değerini bilmez sαhip olduğu sürece αmα bir gün onu kaybettiğinde geç kalınmış tek bir söz: ´Keşke´

anyone able to translate the above please??

my try:

nobody know the value of what they hold in their hands as long as they have it, but one day when they lost it, the last words: if only...

My try, which is very similar to ikicikan´s translation

Nobody knows the value of what is in their hand whilst they possess it, but one day when it is lost, late in the day (they will say) only the word ´keşke´

Keşke means ´if only´. Unfortunately the meaning turns into 2 words. 

It is very similar to the English expression ´You don´t know how much you love someone until you lose them.´ 

Thank you so so much! That couldn´t be anymore clearer !

thanks