The phrase "trusted to luck" implies a disregard for planning and preparation, and a dependence on chance. Its antonyms, therefore, would be terms that convey intentionality, diligence, and responsibility. Some examples of antonyms for "trusted to luck" are prioritizing, foresight, planning, preparing, deliberate action, conscientiousness, care, responsibility, and strategy. By using these opposing words, you are conveying the importance of taking deliberate action and being responsible for your choices. Rather than leaving things to chance and hoping for the best, these antonyms suggest taking control and actively shaping your outcomes.