Well, the simple translation for "(they) are leaving" is "(ils) laissent" or "(ils) quittent".
Before leaving is "avant de partir" in French.
Tu sortirs
Je pars demain.
Au revoir, je pars!orAu revoir, je m'en vais!
Au revoir, je pars!orAu revoir, je m'en vais!
Je vous quitte
'Je pars' means 'I'm leaving' (present tense). 'Tu pars' means 'you're leaving' (present tense).
je m'en vais dans sept jours
"nous partons sans eux" ("sans elles" if 'them' refers to an all-female group)
I THINK it would be:Je ne le quitterai jamais(literally I will never leave him)or possiblyJe ne le quitte jamais(I am never leaving him)
Leaving = Verlassen :)
In order to say "leaving person" in German you say die verlassende Person.