His self-confidence waxes and wanes based on what niceties she chooses to allot him that day. How he chooses to use them is hardly sensible, adding a positive to a larger negative still produces a negative.
His immediate goal is to absorb the happiness and coerce her into giving him more. There is precious little time. If he can't make her love him now then he might miss his chance.
He checked his logic at the airport when he picked her up. Thinking objectively is to no avail, a boy loves a girl and wants his love reciprocated so badly, he is willing to change himself.
The great irony is he has no idea what she wants, he becomes a quiet, jealous, nervous, over thinker. He is making himself less attractive, he lays sleepless thinking about her while she dreams of a better tomorrow.