In a letter to an acquaintance, what's the best way to express literally hope that everything is good at their end?
"I trust you are well" sounds a bit too formal?
"I hope all/everything is well with you" is what I normally write.
I write "I hope this letter finds you in good health".
I hope you are doing well is what I normally write.
I hope things are going well for you. No troubles for you and yours.
If both are semi-religious, a simple "Blessings!" would certainly suffice.
Saying “I hope life is easy on you” is another variation.