This is the best guess that I can offer, since the sentence is quite ungrammatical.

1. If 'cum' stands for the preposition ('with') the writer might be attempting an ablative of quality, mistaking 'crispa' (an adjective meaning 'curly-haired') for a noun; if so, the rest of it would have to be emended to something like 'cum bona [et] crispa [coma] et bonis oculis' to yield the meaning given above. But even this wouldn't be correct, since ablatives of quality do not employ a preposition.

2. If 'cum' stands for the conjunction ('when, since'), the writer has nelected to supply a verb, which here would have to be in the subjunctive (as a causal clause) to make any sense, and the rest of it would have to be emended accordingly to something like 'cum bonam [et] crispam [comam] et bonos oculos [habeas]', and the sense would be 'since you have nice curly hair and nice eyes', implying thereby that such features are the writer's preference.

In any case, it's impossible to make sense out of it as it stands.