Purity's trigger is probably any impure thought or action (however that's judged), towards the Commandment holder. Maybe an explanation as to why Derriere is nude all the time, but we've never seen anyone lust after her so...who knows.
Reticence's trigger is probably speaking of any personal secret you yourself have vowed never to speak of in front of the Commandment holder. I don't see how this could be triggered seeing as how you shouldn't be entrusting someone who is trying to kill you with your most personal secret.
Patience's trigger is probably showing impatience towards the Commandment holder.
Repose's trigger is a bit harder to guess, but I'm assuming it's trigger is taking any sort of action during a cease fire or place of peace or something like that.
As for their effects, it's hard to say what those would be as some of the effects don't really have any sort of "poetic" retribution tied to the curse. Some do, but others don't. Like, for example, Truth's trigger is lying, but then if you lie you get petrified? That doesn't make much sense. Then there is Faith, where the trigger is being unfaithful and the effect is getting your eyes burned out, lol?
And some abilities feel like they would fit other Commandments. Pacifism feels like it should have Love's effects, where people are forced to not be able to fight anybody who shows aggression in the presence of the Commandment holder, instead of aging them. Love feels like it should have Piety's effects, where someone showing hatred towards the Commandment holder is forced to serving them and, by extension, the Demon King. Both of those effects do make sense with their current Commandment, but I feel they would fit more with the others.
Selflessness is the only one that actually has a good effect that has a "poetic" aspect to it's punishment. You act selfish and on your own desires, so you lose your sense of self due to that attitude.
Anyway, I'll go with possible "poetic" aspects for the remaining four.
Purity's effect should be losing the ability to eat, drink, wear, or, even love, anything.
Reticence's effect should be losing your ability to communicate in any form or having anyone communicate with you; You are mute, deaf, you cannot write, you cannot motion to anything; your thoughts are forever a secret to those around you.
Patience's effect should be an increased perception of time flow, meaning your mind is thinking faster than your body can move. You are basically imprisoned in your mind for a what seems like years when only a few seconds has passed in real life.
Repose's effect should just be endless sleep.
And just for fun...
Truth's effect should be that the person cannot hide anything from anyone and everyone who comes into contact with them will know everything about them.
Faith's effect should be that the person grotesquely fused with whatever or whoever they were unfaithful to.
Piety's effect should be placing the person in an endless prayer which links their power to the Commandment holder.