。
Poverty is no obstacle to happiness.
Literal
Poverty [topic-は] happiness [toward-への] obstacle [quotative-と] [contrast-は] does-not-become.
への combines the directional particle へ with の to modify the following noun — 'obstacle toward happiness.' とはならない uses the quotative と with なる in negative, meaning 'does not serve as.' The double は (topic + contrastive) reinforces that poverty specifically is denied as a barrier.