I played for nearly three hours or around 30 days, heroines have trust level 11, and the chevron never once went away. Heroines have never gain any lust and still refuse to stay in a room with a man other then the MC. I've taken off the clothes of Max, Linus, and MC. I do not know why this is happening. The men gain lust if I take the clothes off the girl though.
I'm not sure why the chevron won't go away. It's supposed to just go away after enough nights at the Inn.
The reason why their lust isn't raising when they see naked men is because their own Libido score isn't high enough. The girls need higher Libidos to develop lust on their own. You can see their Libido score in the top-right corner of their "LOVE" page on their character profile. I think they need 80 or 100 before they start gaining lust when the guys are naked.
I'm not sure about other sources of Libido, but their Libido always increases when they get grabbed and progressively stripped by monsters. Go look for monsters based on which ones want which girls and have them get stripped over and over and their Libidos will increase.
In the full game, the monsters with strip attacks will target all the girls, but in the demo, the monsters only go after certain girls. The Orcs will grab the Human, the Goblins in the Mines will grab the Sylph, the Demon Horses in the canyon fissure will grab the Dwarf, the Trolls in the cave past the North-East gate will grab the Gnome.
I forget who grabs the Elf, was it the Ropers in the same fissure where the Demon Horses are?