The person who helps lift Antonio's depression is Bassanio, his close friend and the play's protagonist. Bassanio's determination to pursue love and his desire to marry Portia, a wealthy and intelligent woman, prompts him to borrow money from Antonio. Despite his own financial struggles, Antonio agrees to help and signs a bond with the moneylender Shylock.
The play takes a dark turn when Shylock, seeking revenge for past mistreatments he faced, demands Antonio's flesh as payment for the unpaid debt. Antonio's fate seems sealed, and his depression deepens as he anticipates his impending doom.
But then, Portia steps into the courtroom disguised as a learned lawyer and turns the tables on Shylock. She masterfully exposes the flaws in the bond and saves Antonio's life. This legal triumph not only liberates Antonio from the clutches of despair but also grants him a renewed sense of hope and joy.
Therefore, it's Portia's intervention, her cleverness, and her love for Bassanio that ultimately lift Antonio's depression and restore his happiness.