The three hearts in one another are to convey an ever-growing heart. The feelings are getting deeper and deeper, the love is growing. The heartbeat increases and the heart is filled with joy after an emotional conversation or a great experience.
The growing heart emoji was introduced in 2010 and released as part of the Unicode 11.0 standard. This emoji can be found under the smileys and emotions
category. Because the growing heart emoji has been around for quite some time, it should display correctly in the majority of operating systems.