Collocations for peaceful - adj.

be
become
remain

extremely, fairly, very, etc.
largely, mostly
comparatively, reasonably, relatively

be, feel, look
become
remain

extremely, fairly, very, etc.
utterly
comparatively, relatively
remarkably, strangely, surprisingly
blissfully
The time without her in the house had been blissfully peaceful.

Peaceful is used with these nouns:
assembly, countryside, demonstration, demonstrator, disarmament, evolution, existence, future, interlude, life, manner, march, means, morning, place, protest, protester, resolution, retreat, revolution, scene, serenity, setting, settlement, sleep, solution, surroundings, transition, village, world