Depends on how you count, but I have 365 "say" commands (each "say" command is a new box of text on the screen). I spent the first several days writing the dialogue, and another few days recording voice lines. It helped that I was able to offload a significant amount of programming work to Rakugo (the visual novel engine), but there was still some programming work to get from dialogue in Google Docs to dialogue in game.
My goal with the ending was that there would be some parts where the player would be like "Yes! I knew that was suspicious" and some parts where the player would be like "Wow! I totally didn't see that coming but looking back it makes sense." Hopefully you were able to catch on to at least some clues.
If by "couldn't figure it out" you mean there was some sort of issue such that you couldn't get to the ending, let me know and we can troubleshoot.