What to do if someone says "im in love with you"within a month?

I saw a samiliar question yesterday, only the other way around, that a girl was worried if her boyfriend was cheating, basicly cause he keept to himself a bit too often and would make a fuss about it if she tried to read his textmassages.

I wrote that I think love is among other things based on trust, however it shouldn’t be filled with secrets. So how to make him stop being all that suspecious about you, even though you aren’t keeping secrets from him? I think you need to have a serious talk with him that if he keeps up being insecure about what you do or write with other people.

You won’t be able to handle that slap over your face that you’re not trustworthy in the long run either. His jealousi is a way to show he cares about you, but he needs to learn that it will be the very same thing that makes a distance between you. If you let him have the control by not seeing people only cause he doesn’t trust you, he won’t stop taking that kind of control and possible try to take more advanges of it, untill you’ve had enough of it.

hope you could use some of the advice somehow, or that it brought some thought to attention :)