• smooth crossing, smooth passing
• to be easy in one's mind
• with an easy conscience
• you may rest assured that
• coolly, imperturbably, leisurely, levelly, moderately, on an even keel, placidly, quietly, sedately, serenely
• imperturbability, staidness, tranquillity, tranquilness
• to keep still, to stand still
• make yourself easy about it!