。
I'm looking for someone to love.
Literal
Love [to-する] partner [object-を] am-searching-for.
恋する is a suru-verb form of 恋 ('love'), used adjectivally/adverbially here as a modifier: 恋する相手 = 'a partner (to whom) one loves' / 'someone to love.' 相手 is the general 'other party, counterpart, partner,' used for conversation partners, opponents, and romantic partners alike — context decides. 捜す ('to search for') is used rather than 探す; the former emphasizes searching for a person or something lost.