What a silly question
(Listowel, Co. Kerry, Ireland)
As master Obi-Wan said "What I said was true, from a certain point of view". For example a women says she is blond, but what if she is a natural brunette who dyes her hair? Is she a liar? Some would say yes, others no.
If a overweight women knows men fall in love with her personality and subtracts 20lbs from her weight so she gets more responses is she a liar? In some ways yes...but if a man who responds falls in love with her perhaps the lie turns into a truth of sorts? So in the end the answer is...maybe. As it always has been, as it always will be.
This is as silly a question as "do all men cheat?" No, not all men cheat and not all women are faithful and/or truthful. In fact, faithful and truthful are two different concepts. Are women faithful? If they love their partner and respect him, then yes, they probably will be faithful.
Both partners need to work at a relationship: if the guy disrespects his partner or neglects her, she might be unfaithful, but surely it depends on her character, inclination, opportunity etc etc. The second part of the question "are women truthful" really has nothing to do with the first.
What does truthful mean? Will women tell the truth always? As much or as little as men, I would have thought. Again, depends on the circumstance or character of the woman.
Do I personally tell my husband EVERYTHING? Of course not, and I wouldn't expect him to tell me everything. Little white lies allow relationships to run more smoothly. He certainly would not be appreciative if I told him that I had a steamy dream about the guy(s) from Supernatural, so I won't tell him!
To summarize, the question is really quite sexist - women are as faithful and truthful as men, or as little as men, whichever way you look at it!