献殷勤 ， 取悦
cosy 'up to sb (BrE)(NAmE cozy 'up to sb)(informal)to act in a friendly way towards sb, especially sb who will be useful to you 獻殷勤；取悅
You don't have to cosy up to her.
in∙grati∙ate //verb [VN][no passive] ~ yourself (with sb)(disapproving)to do things in order to make sb like you, especially sb who will be useful to you 討好；巴結；迎合 ：The first part of his plan was to ingratiate himself with the members of the committee. 他的計劃的第一步是拉攏委員會的成員。
His policy is to ingratiate himself with anyone who might be useful to him.