Oh my goodness! I learn French normally, and this is my first day on Finnish; I keep going to write bien!
I've learned well is hyvin. Not sure... anyone else?
It is also that.
But in this case it's more about you being unsure of what you are going to say next so it tranalates
Well... = tuota (noin)... /no... / Umm.... /ööö....
All is well = kaikki on hyvin
Well, i was supposed to write that down but forgot = no, minun piti kirjoittaa se ylös, mutta unohdin
Does that come from the Russian ну?
No it is be used in so many forms and situations in Finnish. It is depending a lot on the context.