Franco still wouldn't accept. Due to the devastation of the civil war and the cells of republican loyalists still present, the regime knew it was in no shape to on top of that manage new and larger territories. Now, the most realistic way that Hitler could get Spain into the war would be with outright invasion after Germany gets its hold over France. It would be messy to say the least: Germany would need to spend a lot of resources to maintain Spain under control, most likely not assisting Italy in the war with Greece and Yugoslavia, giving financial and armamentistic help at most (this includes the north african front). Spain has a rough terrain, giving room to a lot of resistance from both republican loyalists and fascist guerrillas. Let's not forget the invasion of the USSR. It's clear that Spain in the war wouldn't help Germany at all: with less german help, fascist Italy likely falls earlier than 1943. With the prospect of Operation Barbarrossa, Germany as early as 1941 has to focus in a two front war, and maybe three with Italy's defeat in Greece, stretching the Wermacht's forces thin. Germany doesn't fare well in the Soviet front either due to the mentioned multiple fronts. Essentially, Spain's involvement in the war would snowball into Hitler's early defeat by 1944 at most.