You've chosen another interesting piece to read.
(I love the fact that you are so interested in English that you extend your knowledge of our culture and language by reading works such as these).
And so to work!
a. Sunny has several implied meanings beyond the basic meaning of sunshine. For example, "sunny smiles", where it can mean "happy" or "bright" smiles. Here "sunny" is being used as in meaning 1.2 http://www.oxforddictionaries.com/us..._english/sunny
By saying that the grassy mounds possess a "thousand sunny wiles", he is personifying them.
b. Wiles. A "wile" is a stratagem, a trick, a cunning procedure, used to lure or entice you to do whatever the person wants. The common phrase wily fox sums this up, where in that instance it simply means that the animal is "crafty", "cunning" or "clever". However, it can be used in other phrases such as "feminine wiles", where a woman uses all the charm at her disposal to persuade someone to do something. However, underneath there is still the element of cunning, or trickery, as they are getting that person to do what they want. The term is often used with grudging admiration - you don't like what they do, but you admire them for having the skill and brains to be able to do it - such as the fox.
Sunny wiles: The two words together provide contrast and a new meaning: on the surface something appears bright and happy, but underneath a crafty trick of deceit is cunningly concealed.
This is backed up in the earlier lines by the mounds' "watery smiles". A watery smile can be read poetically, in that the mounds had shiny dew on them making them appear bright and pleasant, or it can be read another way. Watery means weak, and if a person has a watery smile it implies it is one that is false, or put on. So, again something which on the surface seems happy and positive, but the fact that the smiles are weak betray their real feelings.
It is also supported by the fact that the grassy mounds finally give away their true feelings by offering their reproval (disapproval/criticism of someone because of their behaviour or actions) by expressing "Death's arrow oft is Love's".
It is unclear why they disapprove of someone's actions. Is it because the maiden died of suicide, because of unrequited love, or simply died of a broken heart because of him, or is it even his heart that has been broken and lies buried? (See my explanation below as to why this final version might be the case).
"Also I am not sure if I comprehend the last two sentences (do they mean the girl committed suicide beceause of unhappy love?)"
I think the meaning is deliberately unclear. That is the wonder of interpretation.
Part of how you comprehend it is determined by whether you look at this poem in isolation, or whether you see it as part a group by including the poem before it and after it. In this case there is a logic, in the titles, which flows: "A Lament", "Dirge" and "Epitaph". It may be that an editor put the three together because there is a logic in doing so, even though the three pieces can stand alone. I don't know if that was the writer's original intention. As he was obsessed by death he could have written any of them at different times as separate poems, or he could have intended them to form a set. I don't know what the writer intended, and of course we can't ask him.
If you look at it as one in a group of three poems, then this one ,"Dirge", is also about the maiden who has died in the previous poem "A Lament". However, if you see them as stand alone pieces, in this poem "Dirge" you have the problem of who "you" and "your" relate to in the poem. They could mean "you" in a general sense where you are the reader reading of events to which you personally are not connected, or it could mean "you" directly as the reader as if you are involved and you are the one carrying out the actions. The final meaning could be "you" in the sense of his beloved, and it is his heart that has been broken and has been buried. But as I said for these multiple interpretations to work the poem has to be a stand alone one.
There is nothing in the poem to suggest that the maiden committed suicide, or even from the previous poem. But there is also nothing to say that she hasn't. You could take it that she has simply died of a broken heart (as a true Romantic!), or as you suggest from suicide. As I said previously, in this poem it could be his heart that was broken and is buried. It is one of those pieces where you have to decide what you feel or think about it, and your interpretation will be as valid as mine.
I would be interested to know your thoughts on this work.
Interested in Language