chet = heart
Alternately spelled jeut, chit, jchet, and likely others, and pronounced somewhere between all of those.
I wrote before that chet (heart) and laying (to play) make all of my favourite Khmer compound words. As far as I know there’s no such word as chet laying (playful heart?), but maybe I’ll slip it into conversation and see what happens. Here are my top chet words (don’t mind the lack of conjugation on the verbs – it’s the only easy thing this language has going for it):
pinh = full; pinh chet = to be really happy (literally: full heart)
Eg. I pinh chet when I learn new compound words in Khmer
peebak = difficult; peebak chet = to be sad (literally: to have a difficult heart)
Eg. I peebak chet because most of my expat friends are leaving Banlung in the next month
kro-um krem = physical exhaustion, aching body; kro-um krem chet = to feel tired and sad and weighed down by life’s hardships, day after day, for a very long time (literally: exhausted aching heart)
Eg. Somnang kro-um krem chet because he works hard in the fields every day but still struggles to survive and to feed his child and sick wife.
awh = to run out of something; awh chet = to stop loving someone or caring about something (literal translation: to run out of heart)
Eg. They used to vote in elections, but now they awh chet because they know that Hun Sen’s party will always manipulate the votes to stay in power and that nothing will ever change.
teuk = water; teuk chet = to be sympathetic and kind; fluid feelings that move easily between people (literally: water heart)
Eg. She teuk chet when she sees her sister struggling to carry the heavy buckets of water back from the well and runs to help her.
chole = to enter; chole chet = to like something (literally: to enter your heart)
Eg. I chole chet the smell of cassava drying in the sun.
Anna's triplog 
This set the office going. The pain in their faces trying to translate teuk chet was funny and in the end they gave up. They said sa-ma-naa-chet is sympathy (Knyom mean sa-ma-naa-chet somrab neak ain – I have sympathy for you). The only thing they could say was that you would use it to say that you are happy to help somebody. Which when they said this sentence did not include the word chole-chet (which means happy). All of this leaves me unsure who to tuk-chet (trust – literary put-heart)
sa-ma-naa-chet? Great! Does sa-ma-naa have another meaning? “teuk chet” was explained to me by my Khmer teacher who doesn’t speak English, so it’s possible I didn’t get the meaning 100% correctly. So are they saying “teuk chet” (water heart) means happy to help? Or helpful maybe?
And what do you mean that chole-chet means happy? Have I been saying it wrong all this time? It means to like something, no? eg. K’nyom chole chet num chake.
If there’s one thing I know for sure about Khmer, it’s that everyone tells you something different. Sometimes I wonder how everyone understands each other.
On reading your beautiful examples, it occurs to me that learning Khmer, perhaps even more than other languages, may be a sort of Rorschach test that brings forth patterns in the user that are more revealing than the actual content of the words.