"Getting down" would mean descending, not ascending.
While I was getting down from the roof, the ladder fell--and I fell with it.
You don't really "get down" the ladder, but use the ladder to get down from somewhere else.
As for your first sentence, it's okay grammatically, but not at all natural to think of a woman on her knees begging someone to marry her. Usually, it's the man who gets down on ONE knee to ask the woman to marry him.
Thank you "Barb_D" Getting up the ladder was easy enough - it was coming down that was the problem.
But in the above sentence from the dictionary has the phrase "getting up the ladder". Can't I use, "getting down the ladder"? If we can use "getting up the ladder".