The kinsman redeemer refuses to bailout Naomi and opts out giving Boaz the right to become the next kinsman redeemer.In the process of being the kinsman redeemer Boaz also consumates Yibum(levirate marriage)
Ruth 4:9 NIV
”9 Then Boaz announced to the elders and all the people, “Today you are witnesses that I have bought from Naomi all the property of Elimelek, Kilion and Mahlon. 10 I have also acquired Ruth the Moabite, Mahlon’s widow, as my wife, in order to maintain the name of the dead with his property, so that his name will not disappear from among his family or from his hometown. Today you are witnesses!”
Should Ruth have insisted on Yibum and then chalitzah with the kinsman redeemer before marrying Boaz?