certainly
cer·tain·ly
 /ˈsɚtn̩li/  adv  
  1 : without doubt : definitely
   It will certainly rain tomorrow.
   This year's festival was certainly much better than last year's.
   Certainly [=surely] you can do a better job than that!
   I'm certainly going to try.
   The new version is most certainly easier to use.
   The snake that bit her was almost certainly poisonous.
  — sometimes used for emphasis
   He didn't get the raise he was hoping for, but he's certainly not complaining.
   I certainly didn't mean to offend anyone.
  2 : of course
  — used to answer questions
   “Can I speak to you for a moment?” “Certainly.”
   “Did I offend you?” “Oh, certainly not.” [=no, you did not offend me at all]
   “May I join you?” “You most certainly may.”