Boaz does his duty of settling the issue of redeeming the land and Ruth at city gate. According to the law, when other near kinsman-redeemer doesn't do his duty, he does in front of ten elders and city people. Through the legal process the marriage was formalized.
As for our learning we must fulfill what we give word to others and always support & encourage for marriages to be done in biblical way.

Watch the sermon: रूत खलियान में|Levirate Marriage
https://youtu.be/gs1vuFUuejg

God bless you
Pastor Prem Kashyap