Loving an insecure person can be frustrating. You always feel like you have to offer praise or reassurance. Not only can that be exhausting, but in trying to do what you think is helpful, you might actually be making matters worse.
When people with insecurities hear something good about themselves, they tend to doubt or even dismiss it, as much research shows. This means, quite perplexingly, that hearing positive feedback can often raise their anxieties, because it may clash with the more pessimistic views they hold of themselves.