it depend on location and how the market put the rental of value..
but for me it cover around 75% monthly repayment

i require to top up the maintenance fee, tax, insurance building and repair...

but u can increase the rental yearly or 2-3 year...depend la..so u can can gain on that part

area with college or university...but the student give u a headache...usually dont take ur property well...
since ur budget around 400k why not buy cheap apt first like 200k or flat just make sure the property maintenance are well also...

the rental vs monthly repayment are hard to archive base to break even...the owner will lose eventually but along the road u have assets...
as for me i own 200k apt rental is 750 and maintenance 75 for loan repayment 820...
so i lost around 200 like that if think about etc...i save for raining day if the house require to fix or what...

my advice is if you wanted to rent just prepare u may perhaps encounter bad rental even it is a family or student...
some maybe pay late some even dont want to pay...make it legal document...
for area u can try it near to ur house more better easy u wanted to spot check
just for start...any way good luck