After you close the dialogue box, Monika will delete her. In this way we finish our Doki Doki Literature Club Plus guide, now you know how to get the secret good ending, just enjoy it to the fullest. The very true ending once you find all three good endings is absolutely. Answer (1 of 2): If done in act 3, she will say Please stop playing with my heart.
Honestly though, the best ending is getting to Act 3 and just hanging with Monika for eternity. It is necessary that we see the CG scenes of Sayori, Natsuki and Yuri, what we will do is write poems for each one, we have to make a save file before writing the first of the poems, we choose the girl to whom we will give the poem, and we must always stay with her by her side, then the CG scene will appear, and we return to be with Monika on the day of the festival, we will create another save file, considering now that if we go over and see Sayori's death we will have the game corrupted, it will start over, having a file saved for the SC scene for each girl, we can then pass to Sayori's death and continue playing normally, when we are in a vacuum with Monika we have to stop talking until she lets us write a poem for her, now we can delete her character file, then we restart the game, and we will be able to solve How to get the secret good ending. There is technically a 'Good' Ending that you can get if you manage to get everyone's CG's before walking in on Sayori hanging around but AFIK it's impossible to save everyone without the use of mods.
