情感(qíng gǎn) - emotion, feeling, sentiment in Mandarin

情感 (qíng gǎn) is emotion in the considered sense: the feelings a poem carries, the emotions an actor has to reach for, the attachment between two people. It is an abstract mass noun and takes 的 freely, as in 深厚的情感, deep feeling.

Register is what separates it from its neighbours. 情感 is the word of essays, reviews, psychology and journalism. In ordinary speech the same idea comes out as 感情, which is the reversed compound and much the commoner of the two. If you are talking about your own relationships over dinner, say 感情; if you are writing about a novel, 情感 is the right choice.

The trap is 感觉. English feeling covers both an emotion and a physical or intuitive impression, but Chinese splits them. 感觉 is what you sense or reckon (我感觉有点冷, I feel a bit cold), and it cannot replace 情感. Nor can 心情, which is your passing mood on a given day rather than emotion as a category.