Yes, Christianity is the only way. That sounds close minded to people, I know. But think about it – if Christ (who was fully God and fully man) died the ultimate death in our place because the "wages of sin is death" and "all have fallen short of the glory of God" then why would God accept you chosing another way? Truth is absolute here, not relative. It's not in fashion. We can't follow the latest religion trend here.
God wants us to love him back. He wants a relationship with us. He wants to bless us. He wants us to put him first, and accept him of Lord of our lives. He wants us to worship him. We were created for all this. People who don't have this relationship with him often feel empty. It's because they "worship" other things instead of God, money, sex, material things, power, etc.
To accept his love and his sacrifice, all you have to do is pray to him and say "God, I know that I have sinned against you or gone against your ways and I'm sorry. I know your son, Jesus Christ, died on the cross for me so that I may have the opportunity to be forgiven for my sins and spend eternity with you. Thank you for this sacrifice, this gift. I now accept Christ as my lord and savior and will walk according to his ways. Amen."
God also wants you to experience his love. All you have to do is say 'yes' in your heart.