"a heart – how shall i say? – too soon made glad. too easily impressed: she liked whate’ershe looked on, and her looks went everywhere."
explain the above poem.

The above lines are from Robert Browning's "My Last Duchess". It describes the duchess in the words of the duke. The Duke is saying that his wife is easily impressed, she likes everything she sees and she sees everything.

Explanation:

My Last Duchess by Robert Browning is a poem about the Duke of Ferrara describing the portrait of the Duchess, his wife. The above lines "A heart- how shall I say? - too soon made glad. Too easily impressed: she liked whate’er She looked on, and her looks went everywhere." were the description of the duchess by the duke. He's saying that she finds happiness easily, everything makes her happy and she gets impressed easily. And that is what he doesn't like. According to him, this is the problem with her. In other words, he is complaining that she's not leaving even a spot of joy for him and he's jealous of that.

imparadis't in one anothers arms  

the happier eden, shall enjoy their fill  

of bliss on bliss, while i to hell am thrust,  

where neither joy nor love, but fierce desire,  

among our other torments not the least,  

still unfulfill'd with pain of longing pines;  

yet let me not forget what i have gain'd  

from their own mouths; all is not theirs it seems:  

one fatal tree there stands of knowledge call'd,  

forbidden them to taste: knowledge forbidd'n?  

suspicious, reasonless. why should their lord  

envie them that? can it be sin to know,

it was surely an odd creature that one made up by reading the historians first and the poets afterwards a worm winged like an eagle; the spirit of life and elegance and charm,   in a kitchen chopping up suet. but these creatures, monst'r however entertaining to the imagination, hast no existence in fact. what one might doth to bringeth h'r to life wast to bethink poetically and prosaically at one and the same moment,   thus keeping in toucheth with fact—that the lady is mrs martin, ag'd thirty-six, did dress in blue, wearing a black coxcomb and brown shoeth; but not losing sight of fiction eith'r—that the lady is a vessel in which all s'rts of spirits and f'rces art coursing and flashing p'rpetually. the moment, howev'r, yond one tries this method with the elizabethan mistress, one brancheth of illumination fails; one is did hold up by the scarcity of facts.   one knoweth nothing detailed, nothing p'rfectly true and substantial about h'r.   hist'ry scarcely mentions h'r.   and i did turn to professeth'r trevelyan again to seeth what hist'ry meanteth to that gent.   i hath found by looking at his chapt'r headings yond t meanteth.