Is it permissible to take a loan from a bank to buy a new house for a newlywed couple if they are unable to afford it, and will this affect their lives and cause God's displeasure?

If borrowing is through a legitimate financing transaction with an Islamic bank, there is no harm in it. As for borrowing with usury from interest-based banks, it is forbidden except out of dire necessity, and renting a dwelling or the availability of Islamic alternatives do not constitute a necessity. Dealing with usury is one of the gravest sins that incurs the war of Allah, as Allah the Almighty says: "O you who have believed, fear Allah and give up what remains [due to you] of interest, if you should be believers. And if you do not, then be informed of a war [against you] from Allah and His Messenger." It is one of the seven destructive sins, and usury is devoid of blessing even if it is abundant, and those who deal with it are cursed. Piety towards Allah is the best beginning for a married couple's life.