The answer is Secure attachment.
Ainsworth theorized that there are three main attachment styles, each one relates to the attachment a child has with their parent or caregiver. There is secure attachment which is a healthy and positive attachment/bond between child and parent/caregiver, insecure avoidant and insecure ambivalent/resistant. The last two are less positive and can have negative implications in the nature of the relationship between the child and caregiver as the child matures.