"Hasn't it occurred to you"

Haven't you realized that I might be trying this hard because I actually do think I know how you feel?

Hasn't it crossed your mind that I might be trying this hard because I actually do think I know how you feel?

^ These two are very similar, but actually slightly different.

The first, using "realized", is asking if the listener knows with certainty that the speaker "might be trying ...."

"Realizations" connote knowledge that happened "all at once" and strikes us as definitely true, immediately. The speaker strongly expected that the listener would have previously "realized".

The second, using "crossed your mind", is asking if the listener has considered the possibility that the speaker "might be trying ...."

"Crossing the mind" is something that happens "at leisure", and connote knowledge that is "being considered".

In context both of them imply that the speaker is /in fact/ "trying this hard because...."

"Hasn't it occurred to you..."

^ This is somewhere in-between the two! An "occurrence" of thought is sudden, but not a "flash of realization" and not certainly true. The listener might say "It had occurred to me, yes", and might still mean he was uncertain.

All three are natural.