I was writing a message to a friend and I got confused about these two expressions ''best'' and ''for the best'' in this particular context:
vs
Which one sounds better?
Thank you so much for your help
As I understand the two phrases, "it would be best to do X" treats doing X as one of the optional courses of action that a person, couple, or other entity may elect to pursue. Other options might be to do U ("see each other all the time"), to do V ("see each other more often than we do now"), to do W ("see each other the same amount as before"), to do Y ("see each other less often"), and to do Z ("see each other one more time and that's it"). The person who says that doing X is best means that it is superior to options U, V, W, Y, and Z, as well as any to others that may have suggested themselves during deliberations over the proper course to take.
In contrast, "It would be for the best to do X" focuses on the general betterment of all concerned, taken on balance. Something that is "for the best" is the most beneficial course—the one that a person taking a dispassionate, utilitarian view of the situation would endorse as optimum. Realistically, some options (the pit or the pendulum, say) don't have a "for the best" alternative; the decision really comes down to choosing your poison—in which case the choice that involves the less agonizing death may be "better" even though in all likelihood it isn't "for the best."
They are equally good, although the first is more concise so you might use that. In that instance, you are using it as an adjective as in OED lemma A 4 (b):
In predicative use. In idiomatic constructions expressing what would be most appropriate, advisable, or desirable for a specified person to do. Cf. better adj. 4.
As complement of to be (esp. in the subjunctive mood) with a personal pronoun or noun as subject and (usually) the infinitive; e.g. he were best (to) go. Now somewhat literary.
The other construction uses it as a noun as part of a fixed phrase as in OED lemma P3 b (a):
for the best: so as to achieve the best outcome or result; aiming at or tending to this, esp. if not at first seeming so.
Again, my advice would be that the two constructions get at the same meaning, so you should go with the more concise one, but they are equally valid from other perspectives.
