The words 잘한다 (to be good) and 자란다 (to be growing), while spelled differently, sound identical when said at a normal speech rate. To go along with the image of the trees, I presume the message is that going to this university will help you excel and grow.
But back to the pronunciation. Korean shows this kind of pronunciation. Of interest here is that when ㄹ is adjacent to ㅎ, the sound of the ㅎ virtually disappears. This can be seen in other words like 발휘 (to exhibit, show a skill, etc.), which again, when pronounced at normal speech rates, is pronounced as [barwee] as opposed to [barhwee].
Another example is 옳다, which means ‘to be correct’. Here it’s a little different because this time it’s a syllable-final consonant cluster ㅀ, but the same principle seems to apply whereby the sound of the ㅎ is overruled by the sound of the ㄹ.
This happens in combinations of ㄴ and ㅎ as well, such as in words like 인하 (to reduce) and 반하다 (to fall for something, someone). At normal speech rates, both are pronounced usually as [inah] and [banada] as opposed to [inha] and [banhada], as the spelling would suggest.
This copy just caught my interest because it made use of this little pronunciation trick. I’m all for smart copies like these.