Summarize this article:

It's really normal for toddlers to fuss and cry during this change, so try not to feel guilty or worry yourself. If your child sees you getting worked up, the situation will escalate. It can be very difficult for a parent not to give in when their child is in distress. You may feel like you are being too cold or rejecting your child, however, your toddler will be less confused and feel more secure if you stay as consistent as possible. Keep a warm, loving tone, and let your toddler know you are there, but do not give in, and do not feel guilty. If your child continues to cry and fuss at night, try to determine what the reasons are. During the day, when your toddler is calm, ask them about it. If it’s just stubbornness and a desire to stay with you at night, just keep being positive and consistent about the change. If it has more to do with fears—of the dark or of monsters—you may be able to resolve the situation by adding a night light, changing some furniture, or devising some sort of security ritual.  Ask them directly what is worrying them. If they don't know, make subtle suggestions to get the bottom of it. Are there shadows that can be fixed with a nightlight? Scary sounds that can be masked with light music? Lie with them for a little bit at night and pay attention to all the sights and sounds. Can they hear a lot of noise coming from other places in the house? Is there a tree that taps on the window? All of these things can be really disruptive to sleep but easily fixed. Reiterate what an exciting change sleeping in bed alone will be, and let your toddler know you are proud of how big and independent they are becoming. Show your toddler how much more room there is in the bed, and remind your toddler of the bedding and toys you picked out together for this moment. Tell your child again how exciting a time this for them. Remind them repeatedly that you are proud of them and try not to let them see you get down on yourself about the decision. It’s possible that you made the change too quickly. You know your child and your family and if after a few days or weeks it still doesn’t feel right—change it. Rather than bring them back to their crib or your bed, try to change your approach. Try sitting in the room until they fall asleep. After a few nights, move to the doorway; after a few more nights, move to the hallway outside the room.

Summary:
Stay calm and patient if your child is very upset about the transition. Determine why your child is resisting. Stay positive, especially if your child is expressing very negative ideas. Consider a more gradual transition if your toddler continues to resist.