The phrase "wilt will not" can be replaced with a number of different synonyms depending on the context of the sentence. Some possible options include decline shall not, wither won't, droop cannot, and sag must not. Each of these synonyms conveys a similar idea of being incapable or unwilling to maintain strength or vitality. Other possible alternatives might include languish cannot, fade must not, or shrivel won't, each of which emphasizes a different aspect of the process of losing energy or vigor. Ultimately, the best synonym for "wilt will not" will depend on the nuances of the specific situation and the effect that the writer wants to achieve.