Google suggests many, as well as a few of my own:

• Clear
• Comprehensible
• Transparent (Although this is usually said as an insult to an individual who has a plan, so I wouldn't recommend it)
• Distinct
• Concise

Although these are all options, yours fits the bill just fine, if not a little formal. For a word in a casual conversation or chat¹ you might like to try:

"Yeah, I get you"

"It's all clear"

In summary, you've used the right word, but there are some good alternatives out there if you wish to use them!

Google suggests many, as well as a few of my own:

• Clear
• Comprehensible
• Transparent (Although this is usually said as an insult to an individual who has a plan, so I wouldn't recommend it)
• Distinct
• Concise

Although these are all options, yours fits the bill just fine, if not a little formal. For a word in a casual conversation or chat¹ you might like to try:

"Yeah, I get you"

"It's all clear"

In summary, you've used the right word, but there are some good alternatives out there if you wish to use them!

EDIT:

To express sympathy, you could (and should) use different terms to those that describe a knowledgeable understanding. If the person is going through a bad time:

• "I feel for you" (when the person is going through a bad time)
• "I know how you feel"

Or, if the person is judging their actions (or themselves) in response to their situation and circumstances:

• "You did the right thing"
• "It's not your fault"
• "You did the best you could"

Or, if you've been through a similar experience:

• "I've been there"
• "We've all been there" (if her situation is a common one)