I loled after reading this:

Despite her many quotes making her out to be strong, Olfina can be killed with a single punch

http://elderscrolls.wikia.com/wiki/Olfina_Gray-Mane

dat irony

...Though the UESP says that she has 75 health. A punch can't do that much damage.

The uesp says nothing of it

The Wikia lies again.
I have hit her with a 20+ damage sword (Adept difficulty) and only damaged 1/3 of her health.

False. She has 50 base health according to Creation Kit, totaling to 75 health with her level.

PC master race - correcting Skyrim Wikia errors since 2011.

Almost funnier than the master race nonsense buying actually doubt that it could be done without heavy enchantments.