The question is about "what to expect from a Bible translation". So, we need to start with a contrast.
First and for reference, consider another translation, one of the best for being most literal...
Mark 4:23-25 (NASB)
23 If anyone has ears to hear, let him hear.” 24 And He was saying to them, “Take care what you listen to. By your standard of measure it will be measured to you; and more will be given you besides. 25 For whoever has, to him more shall be given; and whoever does not have, even what he has shall be taken away from him.”
The Amplified Bible specifically adds enormous numbers of words on purpose. You could call this "clarity via synonyms". This is the reason people use it in Bible study specifically.
Greek and Hebrew verbs often carry much more meaning than verbs in English or other languages. So, the added words can also clarify the nature of the verbs, such as "be listening" from v23 to emphasize a continuous, ongoing action in the present tense.
When it comes to measuring accuracy of the Amplified, simply trim out words that repeat or are unnecessary for a normal sentence. Then, compare that to another translation, such as the ESV or the NASB. Once you do that, the Amplified isn't really that different. So, is it trustworthy? Yes.
Consider this reduction: (shortening long words, removing redundant synonyms, and removing additions [in brackets])
Mark 4:23-25 (Amplified Classic Edition) (words removed)
23 If any man has ears to hear, let him listen.
24 And He said to them, Be careful what you hear. The measure
you give will be the measure that comes back to you—and more will be given to you who hear.
25 For to him who has will more be given; and from him who has
nothing, even what he has will be taken away,
That isn't very different from the NASB (above).
Being familiar with Greek, I know that most of what was cut out was a connotation of the verb forms and definitions in Greek.
Can the Amplified Bible be trusted? Yes, when used for its purpose which is to "amplify" or "elaborate". The purpose of the Amplified Bible is to add one more opinion to the mix when doing "Bible study via multiple translations".
Usually, get a literal translation like the NASB to look up words, the ESV or NLT for a natural flow, The Message for a more "down to earth" phrasing, and the Amplified to add clarity by words. This is usually called a "parallel Bible study". This is one reason the Amplified Bible would go great in a "parallel Bible" if you decide to get one.