* I could not fathom the depth of her grief, and even now, I struggle to understand what she went through. (This sentence emphasizes the difficulty of understanding something complex)
* While I can't fully fathom the intricacies of quantum physics, I strive to understand the basic principles. (This sentence acknowledges limits in understanding, but also highlights the desire to learn)
* The detective tried to fathom the killer's motives, but the crime remained a mystery, impossible to understand. (This sentence uses both words in a narrative context, highlighting the challenge of comprehension)
Remember, "fathom" implies a deeper level of understanding than just "understand," often suggesting a more complex or mysterious situation.