If God is love, how can there be hell?

He loves us enough to give us a choice. Hell is what hell is because the holiness of God is what it is.
God so love the world that he sent his Son to die for us. But God created man with freewill, the ability to choose Him.

When prodigal son left his father's bosom, he opened the gate for the enemy to inflict him. God gave man freewill to choose, but you are not free from the consequences of your choice.

In one sense, God doesn’t send anyone to hell; we send ourselves. We have two options: live with God, or live without God.  Hell is the culmination of telling
God to leave you alone,and finally God says, “Okay.” That’s why the Bible describes it as darkness: God is light; his absence is darkness.

The prodigal son exercised his freewill when he asked for his inheritance. Paul says in Romans 9, who are we—as mere lumps of clay—to answer back to the divine potter?

However do not serve God because you do not want to go to hell. It will be like forcing you to marry someone you didn't want to marry. You must understand how much God loves you, experience His power, believe in Him and trust in His unfailing love.

In Mat 25:31- 46 when Jesus returns in His glory, He will separate the righteous from the sinners. The separation depends on how we threat those in need. Therefore, Christianity is a selfless service to humanity in the love of Christ Jesus. Those who do not follow the path of Christ cannot dwell with a holy and just God.