Some sayings that came up to my mind are..
(Sorry, translation is not good at all><)
「終(お)わりよければすべて良(よ)し」
When it ends happily, we can forget all the difficulties for it.
「為せば成る、為さねば成らぬ、何事も。成らぬは人の為さぬなりけり」
Where there is a will, it will be achieved. Where there is no will, nothing is achieved. If it's not achieved, that's because we are not willing.
「親孝行(おやこうこう) したいときには 親(おや)はなし」
When we finally want to appreciate parents, it's often too late (so we should thank them while they are alive).
「一期一会(いちごいちえ)」
Even if our encounter was something once in a life, let's cherish it because we met.