、。
You can have that flower if you just ask.
Literal
Ask [even-さえ] do-[if-ば], that flower [topic-は] receive-can.
~さえ~ば ('as long as / if only') is a fixed pattern emphasizing minimal sufficient condition — 'just doing X is enough.' Built as masu-stem + さえ + verb ば-conditional. 頼みさえすれば = 'as long as you just ask,' implying that asking alone is the one condition needed for the flower to be given. もらえる is the potential of もらう ('receive').