、。
I'm a wimp who can't bring himself to just ask outright.
Literal
Boldly cannot-ask-out, faint-hearted [attributive-な] I.
A 体言止め (noun-ending) sentence: the final noun 僕 takes the preceding modifiers as attributive description — 'I, who am X.' 思い切って ('boldly, decisively') is the adverbial of 思い切る ('to resolve, to make up one's mind'). 聞き出す ('to ask out, to extract information through asking') is a compound verb 聞く + 出す ('put out, bring forth'). 弱腰 ('faint-hearted, weak-willed') uses 弱 ('weak') + 腰 ('waist/loins') — the waist is metaphorically the seat of resolve.