The deal that Diyoza makes with Clarke is not vastly different from the original deal that she had with Bellamy and broke. The only difference is that it required Octavia's removal. When she made the original deal, she had not yet met Octavia and did not have a reason to feel threatened by her. If she does not have a problem sharing the valley, it does not make sense that she would not have abided by the original deal with Bellamy.