彼はきっとやってくれると思う。

he; him; his; boyfriend

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

surely; undoubtedly; almost certainly; most likely (e.g. 90 percent); sternly; severely; having no slack; rigid; stiff; tight; suddenly; abruptly; instantly

to do; to undertake; to perform; to play (a game); to study; to send; to dispatch; to despatch; to put; to move; to turn (one's head, glance, etc.); to give (esp. to someone of equal or lower status); to let have; to present; to bestow; to confer; to make (a vehicle) go faster; to run (a business); to keep; to be engaged in; to practice (law, medicine, etc.); to practise; to have (food, drink, etc.); to eat; to drink; to smoke; to hold (a performance); to perform; to show; to ease (one's mind); to harm; to injure; to kill; to have sex with; to live; to get by; to get along; to do ... completely; to do ... broadly; to do ... to a great distance; to do ... for (someone of equal or lower status); to do ... to (sometimes with negative nuance); to make active efforts to ...

if; when; and; with; particle used for quoting (with speech, thoughts, etc.); quoting particle; promoted pawn; indicates question (sentence end)

to think; to consider; to believe; to think (of doing); to plan (to do); to judge; to assess; to regard; to imagine; to suppose; to dream; to expect; to look forward to; to feel; to desire; to want; to recall; to remember