Why Shouldn't You Trust her if she Gives You The Best Sex?

In a yesterday's post: Few things you need to know about women on 27. Never trust the woman who gives you the best blow job you’ve ever had.
Why shouldn't u trust her if she gives you the best sex. For me, i think it's just jelousy. imagining how she would satisfy another  man and make him coming at will.  What do you think?