Vocabulary

ਮੰਨੀ ਬੈਠਾ
manni baitha

has already accepted, has already decided (completive aspect)

verb phrase
In this song
Tu Hi Tu · Garry Sandhu
Verse 3: Sultaan
ਦਿਲ ਕਮਲਾ ਤੈਨੂੰ ਮੰਨੀ ਬੈਠਾ boo
dil kamlaa tainu manni baitha boo
My crazy heart has already accepted you as its boo