This is a few expressions related to this concept I found on my dictionary: 难熬 肩负 磨难 Maybe the best is this: 不忍 : 我不忍我妈妈。 Or this: 架不住: 我架不住我妈妈。

I think any emotion can be too heavy to bear. The term just means that "the physical or emotional weight of something is a burden on the carrier and therefore difficult to withstand." So, "Her love is too heavy to bear." means that what she wants out of her boyfriend is so emotionally difficult that I cannot be her boyfriend. "Her nervous tension is too heavy to bear." means that watching how nervous she is about a given situation is painful for me and I would rather not observe her pain.

I would say there are two meanings of the expression. The first one means "it is to hard to carry things". E.g. The bags were too heavy to bear, so I called for the taxi. The second one meaning is "it is too difficult to realise" E.g. The thought of his daughter going to the hospital was heavy to bear. Hope, it helps ;)

Certain thoughts and emotions are too heavy to bear. The guilt is too heavy to bear. If the news of someone's death is too heavy to bear, then that suggests there are feelings of guilt. I can only think of "guilt" as too heavy to bear. Regret, too.

"heavy to bear" is almost always used in the expression "too heavy to bear", which means too difficult to deal with or too hard to handle. For example: "The news of his father's death was too heavy to bear" means the same thing as "The news of his father's death was too difficult to deal with" or "The news of his father's death was too hard to handle". I hope this helps! :)