Being a 20+ yr ffl .... I understand the dealer's viewpoint. He's agreeing with the guy because he may know more about her strength than anyone.
And a .380 is not a bad choice ; shooting and controlling a gun at the range is much different than in a situation where you use it for its intended purpose.
Although some .40 cals have similar weight and trigger pulls now-a-days but the recoil of a .40 is likely going to be noticeably greater than a .380. http://www.chuckhawks.com/handgun_recoil_table.htm
I would be concerned with some women with their first gun being a .40 cal .... I would sell them what ever they wanted to buy .. just like that dealer did.