Black pink can sell 4m

They got 1.5m in a week and we got one more month to go, when digipacks are announced it'll be another 2m. They will get 3.5m from pre orders alone. So 4m is definitely possible

They will be the first ever group after BTS and the fastest group to achieve it

Quote from tesswiwiblink

Should buy two more albums ?

yes

Quote from dujuduju

if the clown buys 1.5m albums then it is possible

aren't we all clowns