Example sentence:
我了解你很累，所以我能理解你为什么拿我出气。
I "understand" you are tired, so I can "understand" why you are giving out your temper at me.
The first understand 了解 means to understand the emotion. The speaker can share the common understanding of this emotion. It's more personal.
The second understand 理解 means to understand the situation from an ojective point of view. It's more distant and facts based.
And in some sentences, both would work but focus on different areas:
我了解你的情况 --> I understand your situation as if I experience what you experience. More personal emotion involved.
我理解你的情况 --> Focus on this whole thing like I get that, I understand that situation. More facts based.
If you go compliant at costomer service, say, they would often reply you that ”我理解你的感受“ I understand your feelings. Noted it's 理解, because with 理解 this word itself also give more distance. Whereas with a friend, you friend might prefer to use ”我了解你的感受“ because it draws these person closer with 了解。
(more)我了解你很累，所以我能理解你为什么拿我出气。
I "understand" you are tired, so I can "understand" why you are giving out your temper at me.
The first understand 了解 means to understand the emotion. The speaker can share the common understanding of this emotion. It's more personal.
The second understand 理解 means to understand the situation from an ojective point of view. It's more distant and facts based.
And in some sentences, both would work but focus on different areas:
我了解你的情况 --> I understand your situation as if I experience what you experience. More personal emotion involved.
我理解你的情况 --> Focus on this whole thing like I get that, I understand that situation. More facts based.
If you go compliant at costomer service, say, they would often reply you that ”我理解你的感受“ I understand your feelings. Noted it's 理解, because with 理解 this word itself also give more distance. Whereas with a friend, you friend might prefer to use ”我了解你的感受“ because it draws these person closer with 了解。