The friendship between Cecelia Monaro and Palmira Medina was initially friendly due to Cece becoming jealous of the engagement between Mira and her best friend/love of her life but they resolved these issues.
Cece and Mira were friends of mutual friends but becoming more friendlier towards each other. When Mira and Tyler became engaged, Cece became jealous of their relationship because she was in love with Tyler.
Cece didn't need to tell Mira about her feelings towards Tyler because Mira knew it by the way they both looked at each other.
Mira confronted Cece about her feelings towards Tyler and told her that she should tell him before it's too late.