I'm curious, because I haven't seen to much on it, but how exactly is trust gained and lost?
Using a rather complex algorithm, where the MC's stats, the girl's personality type, preferences, dominant emotion, interaction types (begging, forcing, rapes, repeat rewards, etc) and so on play a major role. Unless you go code diving, this is about the most precise answer you'll get.
As I've transitioned into training for sex acts I had noticed that both love and trust had started to slip
Do love and trust just naturally degrade over time?
Love and fear/trust slowly revert to 0. Forcing girls into sex acts they're hesitant or reluctant to try also reduces both, but I guess you knew that.
What I'm wondering is if having Lydie as a trainer adversely affecting their affections towards the MC
whether the collars are affecting trust
No. Effects are
usually up-front, and there's no 'secret' code involving Lydie and trust.
whether talking to them actually boosts trust
If you mean the 'chat' interactions, 'encourage' should mostly do it, although materialistic personalities are not very susceptible to it.
(I'm only seeing love +, and sometimes charm+(no idea what charm is suppose to do)
Love and fear/trust can also get maxed, and quite fast if the girl is of low rank. Charm is the 'waitress and service' stat. Although upping charm only happens with very select interactions ('other girls' and service training). Plus certain choices during bedroom visits.
And what exactly does +charm do?
Influences waitress results (plus dancer, service and geisha a tiny bit) in the 'skill bonus' category. Attracts customers who like 'charm'-ing girls while whoring.
Do I just keep talking to them/rewarding them?
Yes. Although you might be maxed, repeated rewards are inefficient, and certain personalities don't respond much to certain types of rewards.
Should I be breaking up my constitution and obedience training with sex training(since neither constitution or obedience training boosts love or trust)?
Up to you. Personally, I prefer to focus on one stat, but choosing the right one is
your job as the master pimp.
solid 10 weeks(I think) of constitution and obedience training across 6 girls is whats ruining the love/trust
Maybe the decay, then. Although you should have only lost ~10-15 points over the ten weeks, unless the girls had some sort of effect happening to them.
If you are a "good" brothelmaster, then the love route is easy, but raising their fear is more difficult - so if they refuse then it's sometimes better to give up.
If all else fails, there are also love/fear potions.
You've clearly followed the "love" route, so trust is not too important (as far as I know).
I
think the main effects of trust are some extra mood and higher chances to act up (refuse to work and so on).
In brief, the game is complex enough that if you want to know
exactly why a given girl is behaving the way she does, I'd need a save and a precise statement of the problem. And it might always turn out ot be a bug or unintended emergent behaviour as well.