、。
Love is a jealous thing that turns healthy eyes cross-eyed.
Literal
Romantic-love [topic-は] jealousy-deep thing [copula-で], normal eyes [object-を] crossed-eye [to-に] causes-to-become.
Two claims joined by the conjunctive で (copula form). 嫉妬深い ('jealousy-deep' = 'jealous') is a compound い-adjective where 深い functions like a suffix meaning 'rich in, full of.' The causative ~させる combines with 斜視に (goal marker) — 'makes (the eyes) into cross-eyed' — a classic に+causative pattern for transforming a state.