"I cannot understand her feelings."
Translation:Je ne peux pas comprendre ses sentiments.
"sentiments" are large: love, hate, fear... the ones that last, or with a large range of more or less strong sensations: sentiment de fierté, de soulagement...(pride, relief...)
"émotions" (verb: émouvoir) are more immediate, you can't repress them, they are instinctive. A sad story will make you cry, for example. They can cause other physical effects: faster heart beat, red face, perspiration...
"sensations" are what your senses or your intuition make you feel ie physical or psychological and physical: : coldness, fatigue...
Interesting Sitesurf- in that the French word "sentiments", as you list the various ones, would usually be called "emotions" in English. But, the second category "émotions", as you describe them, would also be called "emotions" in English. The cognate, "sentiments" in English is usually not used to convey strong and lasting feelings like love, hate, and so on. In general, "sentiments" (En) are a lesser order of emotions (hmm.. hard to express), or at least more temporary. "She's so sentimental- she cries at the drop of a hat".