If I’d known what you were going to do, I’d’ve tried to stop you.
Do they really use this as a verb in French? I have heard French people say “stop !” but I didn’t realize an infinitive form actually exists.
Secondly, the English translation has a double abbreviation which doesn’t exist: Ï’d’ve. It should be either I’d have or I would’ve but not I’d’ve!
Yes, stopper is commonly used as a verb by the French.
I’ve never seen I’d’ve written down before, so it’s unusual in my experience. However, in everyday speech it’s very common.
“Si j’avais su ce que tu allais faire, j’aurais essayé de t’en empêcher.” sounds more natural to me.
empêcher = to prevent here, so the above literally means “Had I known what you were going to do, I would have tried to prevent you from doing it.”