To end up betraying with 〜ことになる

Grammar Explanation: To end up being with 〜ことになる

Makoto explains to Misuzu that he’s been looking into various things since meeting Kanami, such as housing for orphans. However, he realizes what Kanami wishes for is to have her once-kind brother back to the way he used to be.

真(まこと):: 「俺(おれ)が引(ひ)き離(はな)してしまったら」; "If I separate her from him..."; 「叶(かな)実(み)ちゃんを傷(きず)つけて……　裏切(うらぎ)ることになる」; "...I'd be hurting Kanami... I'd end up betraying her."