、。
Troublemakers don't usually turn into model citizens.
Literal
Troublesome-person [subj-が], model citizen [to-に] becoming thing [topic-は] not-much exist.
[Verb]+ことはあまりない ('there isn't much of X happening') is a standard hedged negation, using 'こと + あまり + ない' to say 'it doesn't often happen that...' あまり with a negative has the dual sense of 'not much' and 'not really.' 模範市民 ('model citizen') is a Sino-Japanese compound: 模範 ('example, model') + 市民 ('citizen').