French language Q&A Forum

J'aurai sûrement un quart d'heure de retard

I will probably be fifteen minutes late

Je serai sûrement en retard d'un quart d'heure.

I will probably be fifteen minutes late.

Checking online at Larousse etc., I don't see that "sûrement" means "probably".  "Probably" introduces doubt.  Why not use "surely" or "certainly"? Or for the French, "probablement"?  Which does seem to mean "probably".

I didn't know what else to title my question/issue around this particular subject, but it seems that there's a lack of consistency even here on Kwiziq concerning this subject, evident because of the questions & answers here. There's a "fill-in-the-blanks" exercice that I just revisited titled "Voyage autour du monde" (https://french.kwiziq.com/my-languages/french/tests/overview/1544705) that has two answers which contradict the lesson and feedback.

"Je visiterais d'abord la Californie, puis j'irais en Arizona." According to the lesson, and feedback the correct responses should be "Je visiterais d'abord en Californie, puis j'irais dans l'Arizona." 

Ergo: Confusion Leads to Confusion. 

I was really scratching my head as to why the lesson seemed to think there was a difficulty about whether it should be "dans la rue" or "sur la rue".

Most people in England would say "I live in such and such street", so there's no difficulty at all in saying "J'habite dans rue such and such".

I suspect that to live "on" a street is an American usage, so perhaps the lesson should deal with that in the usual way by translating as "I live in xxxx street (US  I live on xxx street)" ?